He may have been the brother of Abd ar-Rahman ibn Rabiah, who led the attempted conquest of the northern Caucasus Mountains and Khazaria.
Under Uthman, the Muslim armies headed into Armenia for the first time, launching from Syria and led by Habib ibn Maslama al-Fihri.
Habib asked Uthman for help, and he sent 6,000 men led by Salman, marching from Kufa, Iraq.
Salman then penetrated deep into Armenia as far as Khazaria with several conquests and victories with his force of 10,000 men.
He was stopped in a fierce battle with the Khazars, reported to be 300,000 strong, and Salman and all of his troops were killed.