Amorites
The Amorites, (called both Martu and Amurru in the ancient inscriptions), were a once-powerful people who dwelt to the west of Babylonia. There originally ten tribes inhabiting the land of Canaan[1], and there is little doubt that the Amorites were the most powerful tribe in the region at that time.
Sumer
In some of the earliest known sources, the inscriptions of ancient Sumer which date as far back as the first half of the third millennium BC, which is over 500 years before the time of Abraham, the Martu were the rather nomadic people who occupied the lands to the west of Babylonia, including what we know today as southern Syria, Lebanon and the northern parts of ancient Israel. In an inscription of the Sumerian king Ibbi-Sin they are listed as allies in the Sumerian cause against the Elamites[2], the people who were later known as Persians.