Thanagar began in ancient times as a hard world with a primitive and savage culture. They have extensive knowledge of agriculture, mathematics, and philosophy. Among which was utilization of Nth metal, which is a strong metal known for it's ability to negate gravity, making it perfect for the flying Thanagarians.
The Thanagarians once worshiped a pantheon of extradimensional entities known as The Great Old Ones. As they matured, however, the Thanagarians stopped worshiping them, and modern Thanagarians bow down to no higher power.
War Against Gordanians
Thanagar became involved in long and terrible war against the Gordanians, a cruel race of intergalactic slavers. As the situation grew worst for Thanagar, the Thanagarians sent an agent, Lieutenant Shayera Hol, to Earth in order to ensure an alliance between Earth and Thanagar.