Israel/Syria Mixed Armistice Commission
Israel–Syria Mixed Armistice Commission (ISMAC) was the
United Nationscommission for observing the armistice between Israeland Syriaafter the 1948 Arab–Israeli War, as part of the Mixed Armistice Commissions(MAC). [article. V, para. 5, of the General Armistice Agreement] The fourth and last truce agreement, the 1949 Armistice Agreement, was signed between Israel and Syria on July 20, 1949 on Hill 232 near Mahanayim, ending the formal conflict in the former British Mandate of Palestine. The Israeli side was represented by Lieutenant Colonel Mordehai Maklef, Yehoshua Penman and Shabtai Rosen, and the Syrian side by Colonel Fawzi Selo, Lieutenant-Colonel Mohamed Nasser and Captain Afif Sizri on behalf of Syria. [ [http://domino.un.org/unispal.nsf/9a798adbf322aff38525617b006d88d7/e845ca0b92be4e3485256442007901cc!OpenDocument UN Doc S/1353] Syria Israel Armistice Agreement of 20 July 1949] While the armistice agreements with Syria concluded the 1948 Arab–Israeli War, they did not mark the end of the Arab-Israeli conflict.
A feature of the Israeli/Syrian General Armistice Agreement (GAA) was the provision for the establishment of a special DMZ between the countries. The DMZ established by the GAA between Israel and Syria was "defined with a view toward separating the armed forces of the two parties in such manner as to minimize the possibility of friction and incident, while providing for the gradual restoration of normal civilian life in the area of the DMZ, without prejudice to the ultimate settlement." [article. V, para. 2, of the General Armistice Agreement] This provision had to be made because of the divergent viewpoints of the two parties during the armistice negotiations as to the sovereignty of the areas within the boundaries of the former British Mandated Territory which had been occupied by Syrian troops. A Compromise agreement was finally reached under which the disputed areas were to be completely demilitarised. The armistice demarcation lines between Syria and Israel outside of the DMZ coincided with the international boundary.
The Israeli/Syrian DMZ comprised 250 square kilometres of land, divided into three areas, to the east and to the North-East of Lake Galilee. Under the provisions of the GAA the Chairman of the Israeli-Syrian Mixed Armistice Commission (ISMAC) was given responsibility for the “gradual restoration of normal civilian life in the area” and it was his task to authorize the “return of civilians to villages and settlements in the DMZ”. [Article. V, paras.2 & 5e, of the General Armistice Agreement] [Memorandum to the Chairman of the ISMAC from the Israel Ministry of Foreign Affairs of 27 December 1954] The chairman of the Israel/Syrian Mixed Armistice Commission was given duties and powers in addition to those held by the chairman of the other three Mixed Armistice Commissions.
The Headquarters of the ISMAC was situated at the Customs House near Jisr Banat Yakub and at Mahanayim, [article. VII, para. 2, of the General Armistice Agreement] The overall HQ of the controlling body of the 4 MACs, the UNTSO, after 3 relocations ended up in
Government House Jerusalem.
With the instigation of the final truce to the 1948 Israeli war of Independence the only areas of the northern sector of former British Mandate of Palestine not occupied by Israel were those areas along the Jordan River controlled by Syria. Israel insisted on retaining all the territory it had occupied that had been designated for a Palestinian state. However, it demanded that Syria not be allowed to remain in the areas that Syria had occupied. UN acting mediator
Ralph Bunchewas able to convince Syria to withdraw on the understanding that the sovereignty of the 3 Israel/Syria DMZs created (totalling 66.5 sq. miles) would remain undetermined until a final peace settlement was achieved.
Practically, all the work carried out by the ISMAC was cantered upon the problems arising in the DMZ. The pattern of disputes concerning the DMZ generally followed three lines:
(a) disputes about establishing of new and rebuilding of old settlements in the area;(b) disputes about the number of civilians to be readmitted into the area; and(c) disputes about the removal of military installations in the area.
On the first point: In 1950, a new kibbutz at Beit Katzir was established in the southern DMZ. Like most of their kibbutzim in troubled areas, it was fortified with trenches with a double-apron of barbed-wire fence from behind which its settlers sallied out to cultivate the surrounding land, digging irrigation canals to channel the water from Lake Galilee with such vigour that before long no Arab farmer in the area was allowed into the stretch of land between the kibbutz and the lake. The MAC decided that the new settlement at Beit Katzir erected by returning Israelis had been established without the agreement of the Chairman of the MAC, it was fenced in, so as to be more the nature of a military outpost and that the fence should therefore be removed. Israel complied with that decision. [ [http://domino.un.org/unispal.nsf/9a798adbf322aff38525617b006d88d7/6b189672cac9e58a85256d9f006554b8!OpenDocument A Report Dated 12 February 1950] From The Chief Of Staff Of The Truce Supervision Organization In Palestine To The Secretary-General On The Activities Of The Mixed Armistice Commissions]
The second point “the return of civilians” to the DMZ gave rise to a good deal of disputes. The chairman of the MAC could interpret his duties and powers under the GAA only in such a way so as to permit the return of Palestinian, Syrian and Israeli civilians in numbers corresponding to the number of Palestinian, Syrian and Israeli civilians prior to the end of the British Mandate. [article. V para. 2, of the General Armistice Agreement] According to this principle, the MAC Chairman authorized
Palestinian, Syrian and Israeli civilians to return to the DMZ to resume their civilian life there as of 8 September. By the end of January 1950, the number of Israelis returned to the area under this ruling, roughly equalled the number of Israelis who had resided there at the end of the mandatory regime. [ [http://domino.un.org/unispal.nsf/9a798adbf322aff38525617b006d88d7/6b189672cac9e58a85256d9f006554b8!OpenDocument A Report Dated 12 February 1950] From The Chief Of Staff Of The Truce Supervision Organization In Palestine To The Secretary-General On The Activities Of The Mixed Armistice Commissions]
The number of Palestinian and Syrians returned by the end of January 1950 amounted to approximately 75% of those living there at the expiration of the Mandate. At first, Syrian representatives opposed the ruling of the chairman and requested that the number of returning civilians be limited. At a later stage, however, the Syrian representatives accepted the Chairman of the MAC’s ruling as to the number of returning refugees, but the Syrian delegation were still opposed to the MAC Chairman's ruling that new settlements may be erected by returning settlers, both Arab and Israeli. [ [http://domino.un.org/unispal.nsf/9a798adbf322aff38525617b006d88d7/6b189672cac9e58a85256d9f006554b8!OpenDocument A Report Dated 12 February 1950] From The Chief Of Staff Of The Truce Supervision Organization In Palestine To The Secretary-General On The Activities Of The Mixed Armistice Commissions]
This Syrian attitude appeared to the Chairman of the MAC to be partly motivated by the disparity of economic conditions under which the returning Arab and Israeli civilians live. The returning Israeli settlers were well equipped with building materials, machinery and agricultural implements and were therefore, in a position speedily to establish permanent settlements which was considered by Syria to be of potential military value. On the other hand the returning Arab refugees often arrived completely destitute in their former villages, most of which have been levelled to the ground by the Israeli forces prior to their withdrawal from the area after the signing of the Israeli-Syrian Armistice Agreement. [ [http://domino.un.org/unispal.nsf/9a798adbf322aff38525617b006d88d7/6b189672cac9e58a85256d9f006554b8!OpenDocument A Report Dated 12 February 1950] From The Chief Of Staff Of The Truce Supervision Organization In Palestine To The Secretary-General On The Activities Of The Mixed Armistice Commissions]
The Chairman of the ISMAC felt there was no doubt that the dispute could have been easily resolved if the economic conditions of civilians returning from both sides could have been somewhat equalized by providing the returning Arab refugees with building materials and with agricultural implements. However, the Chairman of the ISMAC and the Chief of Staff UNTSO had no means at their disposal to assist the rehabilitation of Arab refugees returning to their homes nor were they in a position officially to enlist the co-operation of any of the other United Nations agencies in the area that might conceivably be concerned with this problem. However, the representative in
Beirutof the United Nations Relief for Palestine Refugees (fore runner of the United Nations Relief and Works Agency for Palestine Refugees established on 8 December 1949) [ [http://domino.un.org/unispal.nsf/9a798adbf322aff38525617b006d88d7/af5f909791de7fb0852560e500687282!OpenDocument UN Doc A/RES/302 (IV)] General Assembly Resolution 302 of 8 December 1949 Establishing UNRWA, Advisory Commission/UNCCP consultations and Economic Survey Mission] and the International Red Crossdid provide limited aid to the returning Arab refugees. [ [http://domino.un.org/unispal.nsf/9a798adbf322aff38525617b006d88d7/6b189672cac9e58a85256d9f006554b8!OpenDocument A Report Dated 12 February 1950] From The Chief Of Staff Of The Truce Supervision Organization In Palestine To The Secretary-General On The Activities Of The Mixed Armistice Commissions]
As to the third point, the ISMAC, with the co-operation of both parties, had by12 February 1950 completed the removal of military installations, mines and fortifications from the demilitarized zones as specified in the GAA. [ [http://domino.un.org/unispal.nsf/9a798adbf322aff38525617b006d88d7/6b189672cac9e58a85256d9f006554b8!OpenDocument A Report Dated 12 February 1950] From The Chief Of Staff Of The Truce Supervision Organization In Palestine To The Secretary-General On The Activities Of The Mixed Armistice Commissions]
Failure Of The Mixed Armistice Commission To Hold Regular Meetings
Israel refused to attend the meetings of the Israel/Syria Mixed Armistice Commission since 1951. This refusal on the part of Israel not only constitutes a flagrant violation of the General Armistice Agreement, but also contributed to an increase of tension in the area. The Security Council itself strongly condemned the attitude of Israel, in its resolution of 18 May 1951, as being "inconsistent with the objectives and intent of the Armistice Agreement" [ [http://domino.un.org/unispal.nsf/9a798adbf322aff38525617b006d88d7/7b0d9e1d08cc405e852560c2006ec543!OpenDocument UN Doc S/RES/93 (1951) S/2157 of 18 May 1951] Mideast situation/Return to permanent peace in Palestine - Israel, Syria to observe Armistice Agreement]
On 20 June 1951 Israel informed the UNTSO that it would no longer attend meetings of the Syrian/Israeli MAC as long as complaints involving the DMZs were on the agenda. Israel argued that Israel alone had sovereignty over the DMZs and that Syria had no rights and therefore, no standing to discuss the zones. Israel immobilized the MAC working within the DMZ. Israel also refused to allow UN observers to carry out a cadastral demarcation of the line of the DMZs and thereby no one was ever sure exactly where the line lay
The Israel position concerning the competence of the MAC to deal with questions connected with the DMZ was a direct contradiction of the Syrian position on the same subject. The Israel position was set out in the following extracts from the memorandum from the Israel Ministry of Foreign Affairs of 27 December 1954:
"…The absence of any Syrian "locus standi" in the zone is demonstrated conclusively in the limitation of the competence of the Mixed Armistice Commission with regard to matters of the DMZ. According to paragraph 5 (c) of article V, it is the Chairman of the Commission (or the Chief of Staff), and not the Commission, of which Syria is a member, that is responsible for ensuring the implementation of article V, governing the DMZ."…
"It is evident ... that no distinction can be deduced between the Chairman's jurisdiction over civilian matters and his competence with regard to the military aspects of article V. Indeed, paragraph 5 (c) of that article defines the Chairman's responsibility as ensuring the full implementation of the article without any difference whatever between its civilian life clauses and its military provisions. [Article. V, paras.2 & 5e, of the General Armistice Agreement] < [ [http://domino.un.org/unispal.nsf/181c4bf00c44e5fd85256cef0073c426/a75451c1745d5941052567230071172f!OpenDocument Report dated 6 January 1955] by the Chief of Staff of the United Nations Truce Supervision Organization in Palestine to the Secretary-General on complaints concerning the observance of the General Armistice Agreement between Israel and Syria]
The principle of the personal responsibility of the ISMAC Chairman was followed in practice by the Israeli delegation throughout the years of the ISMAC existence, except when otherwise agreed to by Israel (as for instance in a number of MAC discussions held before 1951). The chairmen of the ISMAC had taken up and settled numerous questions concerning the DMZ directly with the Israeli representatives. From July 1954 to January 1955 at least, 15 such matters, regarding civilian as well as military questions of the zone, had been brought by the MAC Chairman before the Israel authorities. [ [http://domino.un.org/unispal.nsf/181c4bf00c44e5fd85256cef0073c426/a75451c1745d5941052567230071172f!OpenDocument Report dated 6 January 1955] by the Chief of Staff of the United Nations Truce Supervision Organization in Palestine to the Secretary-General on complaints concerning the observance of the General Armistice Agreement between Israel and Syria]
Syria, however, persisted in Israel’s opinions in attempts to create for itself a position which would entitle it to intervene in a territory that lay outside its State boundaries, and in several instances questions concerning the DMZ had appeared at Syria’s insistence on the agenda of the MAC. It was evident that Israel could not acquiesce in the attempts by Syria to gain rights which were not its own and is bound to remain consistent in upholding the basic tenet of the GAA the exclusion of Syria from any rights within the DMZ, even if this sometimes it necessitated the Israeli delegation absenting itself from meetings of the MAC at which Syria sought to intervene in questions affecting the zone. [Israel Ministry of Foreign Affairs of 27 December 1954 annex B, para. 3 and paras. 7 to 9]
The Syrian position on this matter was contained in the first part of the aide-mimoire of the Syrian Ministry of Foreign Affairs. This aide-memoire also refers to the "note verbale" of the Syrian Ministry of Foreign Affairs to the Chief of Staff dated 17 June 1954 [S/3230] . The Syrian position may be summarized as follows: the MAC being competent to supervise the execution of the provisions of the GAA, including article V, relating to the DMZ, was empowered to deal with complaints submitted by the parties relating to the implementation of article V. Paragraph 5 (c) of article V of the armistice agreement refers to the responsibility of the Chairman of the MAC and UN observers for ensuring the full implementation " of the article, whereas the first paragraph of article VII provides that the MAC shall supervise the execution of the provisions of the agreement.
Such conflicting views as to the competence of the MAC in relation to the DMZ resulted in the failure of the MAC to hold regular meetings since 20 June 1951, the Syrian delegation refusing to withdraw complaints relating to the DMZ from the list of complaints pending before the MAC, while the Israel delegation insists that such complaints be deleted.
"There are differences of opinion between the parties to the Armistice Agreement on the meaning of various provisions of article V, including those which relate to the Chairman's powers, but neither party requested an interpretation by the MAC in the manner established by Article VII of the agreement, and the Chairman has had to rely on his own interpretation, knowing that in many cases it would probably be found unacceptable by one party or by both and that the requests of the Chairman of the ISMAC were likely to be met with refusal on the ground that the Chairman of the ISMAC was exceeding his powers or acting in some other manner contrary to the provisions of the Armistice Agreement. [UN Doc S/2389, para. 4]
31 December 1952, Following incidents in the area of
Tel Katzir, the Israel General Staff officer in charge of the Israeli delegation to the MAC stated that the terrain features prevailing in the area south-west of Lake Galilee (Lake Tiberias) imposed certain security considerations, and that Israel considered that area as a security zone. The area east and south of Tel Katzir was a vital part of that security zone, and Israel could not accept the claim of free access of Arab farmers from Tawafiqto some fields within the area. The Chairman of the MAC did not recognized the Israeli claim that this area is vital to Israel's security.
The fighting in the spring of 1953 resulted in Syria managing to gain control of the village of
al-Hammain the southern zone, all of the tiny northern zone and the uninhabited narrow stretch of land on the east side of the Jordan River in the central zone. Israel lay claim the remainder, most of the southern zone and the entire central zone west of the Jordan River.
September 1953 Israel advances plans to divert water to help irrigate the coastal Sharon Plain and eventually the Negev desert and launches a diversion project on a nine-mile channel midway between the Huleh Marshes and Lake Galilee (Lake Tiberias) in the central DMZ to be rapidly constructed. Syria claims that it would dry up 12,000 acres of Syrian land. The UNTSO Chief of Staff Major General
Vagn Bennikeof Denmark noted that the project was denying water to two Palestinian water mills, was drying up Palestinian farm land and was a substantial military benefit to Israel against Syria. The US cut off aid to Israel. The Israeli response was to increase work. UN Security Council Resolution 100 [ [http://www.un.org/documents/sc/res/1953/scres53.htm UN Doc S 3182] UN Security Council Resolution 100 of 27th October 1953] “deemed it desirable” for Israel to suspend work started on the 2nd September “pending urgent examination of the question by the Council”. Israel finally backed off by moving the intake out of the DMZ and for the next three years the US kept its economic sanctions by threatening to end aid channelled to Israel by the Foreign Operations Administration and insisting on tying the aid with Israel's behaviour. The Security Council ultimately rejected Syrian claims that the work was a violation of the Armistice Agreements and drainage works were resumed and the work was completed in 1957. [ [http://domino.un.org/UNISPAl.NSF/f45643a78fcba719852560f6005987ad/cbf1b65e5de19c1c052564e30046d1b3!OpenDocument UN Doc S/4271] Letter dated 25 February 1960 from the representative of Israel to the President of the Security Council 25 February 1960]
30 June 1954, an Israel armoured launch attacked the Syrian post of
El Koursi, situated on Syrian soil, with its 20-mm. gun. [ [http://domino.un.org/unispal.nsf/181c4bf00c44e5fd85256cef0073c426/a75451c1745d5941052567230071172f!OpenDocument Report dated 6 January 1955] by the Chief of Staff of the United Nations Truce Supervision Organization in Palestine to the Secretary-General on complaints concerning the observance of the GAA between Israel and Syria]
31 June 1954,two Israeli armoured launches attacked the Syrian post of El Koursi with their 20-mm. and 57-mm. guns, this time with the support of Israel field artillery sited in the defensive area. This artillery continued firing for approximately I hour and 45 minutes, causing material damage to the post. [ [http://domino.un.org/unispal.nsf/181c4bf00c44e5fd85256cef0073c426/a75451c1745d5941052567230071172f!OpenDocument Report dated 6 January 1955] by the Chief of Staff of the United Nations Truce Supervision Organization in Palestine to the Secretary-General on complaints concerning the observance of the General Armistice Agreement between Israel and Syria]
Israeli kibbutzniks from Tel Katzir had been conducting illegal work using tractors on lands belonging to the civilian Arab population of the southern DMZ (Tawafiq) when on 5. December 1954 in the southern DMZ, a group of 8 armed regular Israel police had fired on two civilians from Tawafiq with rifles and automatic weapons. [ [http://domino.un.org/unispal.nsf/181c4bf00c44e5fd85256cef0073c426/a75451c1745d5941052567230071172f!OpenDocument Report dated 6 January 1955] by the Chief of Staff of the UNTSO in Palestine to the Secretary-General on complaints concerning the observance of the GAA between Israel and Syria]
8 December 1954 A party of 5 Israeli soldiers were captured several kilometres inside Syrian territory. After interrogation the soldiers admit to carrying out a mission to retrieve equipment previously placed to tap phone calls in Syria.
12 December 1954 Israel forced a Syrian civilian airliner to land in Israel in the first recorded skyjacking after Israel claimed it had entered Israel's airspace illegally, the Israeli claim was admitted to be false by Israeli Prime Minister
Moshe Sharretto the Israeli Knesseton 17 January 1955.Avi Shlaim. (2000) The Iron Wall;Israel and the Arab World Penguin Books ISBN 0-140-28870-8 p 116] Israeli war-planes forced a Syrian Airways Dakota passenger craft carrying four passengers and five crewmen to land at Lydda airport inside Israel. [New York Times, 12/13/54.] The passengers were interrogated for two days before international protests, including strong complaints from Washington, finally convinced Israel to release the plane and its passengers. [Associated Press, New York Times, 12/15/54] The plane had been forced down so that the passengers could be used as hostages for the Israeli soldiers caught on espionage duties in Syrian territory.
11 December 1955, Under the command of
Ariel Sharon, Israel(Operation Kinneret) sent two paratroop battalions backed by artillery and mortar batteries and attacks Syrian Gun emplacements at Buteiha Farm and the village of Kursi (El Koursi) outside the DMZ, on the North-Eastern shore of Sea of Galilee(Lake Tiberias). 56 Syrians including 3 women were killed and 3 Syrian soldiers taken prisoner. Israel lost 6 killed. The US expressed "shock" at Israel's unprovoked act of aggression and "flagrant violation" of the armistice agreement. [Avi Shlaim (2000) p.150 Avi Shlaim contends that Israel was testing out the extent of co-ordination between Egypt and Syria vis a vis the Mutual Defence pact signed between Egypt and Syria in October 1955. Avi quotes Bar-On in “Challenge and Quarrel” p.56-58. “If Nasser failed to rise to the challenge, the hollowness of his pledge would be exposed before the entire Arab world; if he did rise to it, this local incident might develop into a general confrontation with Egypt.”]
30 October 1956 When Israel attacks Egypt across the Sinai peninsula in co-ordination with an Anglo-French attack on Suez. The remainder of the Palestinians living in the DMZs were driven into Syria.
*AOL - Area of Limitations
*AOS - Area of Separation
*DMZ - Demilitarised Zone
Hashemite Kingdom of Jordan/Israel Mixed Armistice Commission
*ISMAC - Israel/Syria Mixed Armistice Commission
Mixed Armistice Commissions
*OGE - Observer Group Egypt
*OGG - Observer Group Golan
*OGG-D - Observer Group Golan - Damascus
*OGG-T - Observer Group Golan - Tiberias
*OGL - Observer Group Lebanon
*UNDOF - United Nations Disengagement Observer Force
United Nations Emergency Force
United Nations Interim Force in Lebanon
United Nations Truce Supervision Organization
* Shlaim, Avi 2000 "The Iron Wall Israel and the Arab world" Penguin Books ISBN 978-0-140-28870-4 ISBN 0-140-28870-8
* [http://www.un.org/Depts/dpko/missions/untso/ Official website]
Wikimedia Foundation. 2010.
Look at other dictionaries:
Mixed Armistice Commissions — The Mixed Armistice Commissions (MAC) is an organisation for monitoring the ceasefire along the lines set by the General Armistice Agreements. It was composed of United Nations Military Observers and was part of the United Nations Truce… … Wikipedia
SYRIA — SYRIA, state in southwest Asia. Although constantly subject to changes, the country s boundaries were primarily: Ereẓ Israel to the south, Asia Minor (Turkey) to the north, Mesopotamia to the east, and the Mediterranean to the west. Biblical and… … Encyclopedia of Judaism
ARMISTICE AGREEMENTS, ISRAEL-ARAB — (1949), series of bilateral agreements concluded between Israel and Egypt (Rhodes, Feb. 24, 1949), Lebanon (Rosh ha Nikrah, March 23, 1949), Jordan (Rhodes, April 3, 1949), and Syria (Maḥanayim, July 20, 1949), terminating the military phase of… … Encyclopedia of Judaism
Israel — /iz ree euhl, ray /, n. 1. a republic in SW Asia, on the Mediterranean: formed as a Jewish state May 1948. 5,534,672; 7984 sq. mi. (20,679 sq. km). Cap.: Jerusalem. 2. the people traditionally descended from Jacob; the Hebrew or Jewish people. 3 … Universalium
Syria — /sear ee euh/, n. 1. Official name, Syrian Arab Republic. a republic in SW Asia at the E end of the Mediterranean. 16,137,899; 71,227 sq. mi. (184,478 sq. km). Cap.: Damascus. 2. a territory mandated to France in 1922, including the present… … Universalium
Israel — This article is about the modern country. For other uses, see Israel (disambiguation). State of Israel … Wikipedia
1949 Armistice Agreements — The 1949 Armistice Agreements are a set of agreements signed during 1949 between Israel and its neighbors Egypt, [ [http://domino.un.org/unispal.nsf/9a798adbf322aff38525617b006d88d7/9ec4a332e2ff9a128525643d007702e6!OpenDocument Egypt Israel]… … Wikipedia
Arab citizens of Israel — Infobox Ethnic group group = Arab citizens of Israel عرب إسرائيل (العرب الإسرائيليون) rlm;ערבים אזרחי ישראל Emile Habibi • Ahmed Tibi • Salah Tarif caption = population = 1,144,000 plus270,000 in East Jerusalem and the Golan Heights (2006) 19.7%… … Wikipedia
United Nations Truce Supervision Organization — UNTSO is an acronym for United Nations Truce Supervision Organization, an organization founded on 29 May 1948 [ [http://domino.un.org/unispal.nsf/9a798adbf322aff38525617b006d88d7/a9a8da193bd46c54852560e50060c6fd!OpenDocument UN Doc A/RES/186 (S… … Wikipedia
List of attacks against Israeli civilians before 1967 — Objections by the Arab population to the planned creation of a Jewish state in Palestine included violent means, such as anti Jewish riots in 1920 21, the of 1929, in Hebron and Safed, the Arab Revolt of 1936 39 during which the Tiberias massacre … Wikipedia