As Bakr got older, he was able to form a fighting force along with his family members and other Arabs into a nomadic federation just as Wael advised.
Banu Bakr's original lands were in Najd, in central Arabia, but most of the tribe's bedouin sections migrated northwards before Islam after winning the Battle of Dhi Qar against the Sasanian Empire, and settled in the area of Upper Mesopotamia, on the upper Euphrates.
Later on they pushed against the Persians eastward and managed to conquer the Tigris banks as well; where they gained a foothold of the whole Mesopotamia territory.
[1][2] The tribe is distinct from their distant cousins Bani Bakr ibn Abd Manat of Tihamah, who lived in the Hejaz and the costal area and had important interactions with Prophet Muhammad.
In late 1257, as the Mongolian army marched towards Baghdad, Banu Bakr, just like the rest of Sunni Arab tribes, has had already retreated southwest towards inner Arabia with the first exiting caravan.
They were never able to recover their losses from the Mongolian blow by Hulegu Khan which dried up their lands thus driving them along with their cattle out of Mesopotamia.
During the Islamic Prophet Muhammad's era the Banu Bakr tribe was involved in various military conflicts.
Using their Arabian stallions and Damascusian steel swords, they became important for traveling caravans and provided paid security services for the protection of goods and camel cargo.
At some point, it became common to hear of the Banu Bakr boys and young men attacking first due to their bedouin and firm nature.