Assyrian conquest of Aram
Assyrian conquest of Syria (854 BC - 846 BC) was an invasion by the armies of Assyria led by King Shalmaneser III to conquer Syria, then named Aram. The war resulted in the formation of what became known as the 12 kings alliance against Assyria. It peaked with the 853 BC Battle of Qarqar which was indecisive but nonetheless resulted in Assyria withdrawing their forces due to them having suffered heavy casualties. Despite these losses the war continued until 846 BC, but ultimately this particular invasion was a failure. Eventually however King Shalmaneser III did conquer Syria and most of Palestine, and Syria was incorporated into the Assyrian Empire. 
Reasons for the invasion 
Assyrian King Shalmaneser III had numerous enemies during his reign. These included the kingdoms of Egypt, the Ammonites and the Kingdom of Israel. Wars between Shalmaneser III and these nations were ongoing throughout his region.