The countries of Armenia, Azerbaijan and Georgia have much recent history in common. All three were at some time independent, with Christianity as their main religion. The Kingdom of Armenia was actually the first state in the world to adopt this religion. All were colonized by Russia (and in the case of Armenia also by the Ottoman Empire), and all regained independence in 1918, but were later annexed by the Soviet Union, to become independent again when the Soviet Union collapsed in 1990.