The Merkava was designed soon after the Yom Kippur War (1973). The Israelis initially wanted to acquire Chieftains from Great Britain, but the British Government decided in 1969 to cancel any weapon deliveries to Israel, and therefore the project was halted. This prompted the designing of a local tank, which would become the Merkava. The first prototype was ready in 1974, heavily drawing on lessons learned from the 1973 October War. In short, the Merkava was the embodiment of the ideal MBT for Tsahal. Combining speed, endurance, firepower and accuracy with high survivability requirements and an emphasis put on crew protection. (courtesy of www.tanks-encyclopedia.com/modern/israel/Merkava.php)