Biblical chronologies for the two Israelite kingdoms in the 8th century BC are both profuse and perplexing. Some of the reign lengths or synchronisms are given from the start of a sole reign, while others are given from the start of a coregency, or, in the case of Pekah, from the start of a rival reign. Thiele maintained that the key to understanding these records lies in a proper appreciation of the growing threat from Assyria that both kingdoms faced. In 754 BC, Ashur-nirari V led the Assyrians against Arpad in northern Aram. His successor Tiglath-Pileser III warred against Arpad in the years 743 to 740 BC, capturing the city after three years. In face of this threat, Rezin of Damascus made an alliance with Pekah of Israel, and the two were therefore enemies of the pro-Assyrian king of Judah, Ahaz (). Meanwhile, Menahem, ruling in Samaria, sent tribute to Tiglath-Pileser (Biblical Pul) in order to "strengthen his hold on the kingdom," (2 Kings 15:19), apparently against his anti-Assyrian rival Pekah. According to Thiele, it is the existence of strong pro-Assyrian and anti-Assyrian factions in both Israel and Judah that explains the way the chronological data for the time were recorded: