In the wake of the War in Lebanon (1982), Israel engaged in negotiations brokered by the United States with Lebanon concerning the withdrawal of foreign forces from Lebanon and related arrangements. After months of discussion, an agreement was reached on 17 May 1983 that provided for the withdrawal of Israeli forces from Lebanon and noted that "they consider the existing international boundary between Israel and Lebanon inviolable." Israel committed itself to withdraw from southern Lebanon in return for specific security arrangements in the south and some elements of normalization approaching, but not quite becoming, a peace treaty. It was an important milestone in Israel's relations with the Arab states. Although signed and ratified by both states, the government of Lebanon abrogated the agreement in March 1984 under heavy pressure from Syria.
Historical Dictionary of Israel. Bernard Reich David H. Goldberg. Edited by Jon Woronoff..