The Iron Throne is the throne upon which the King of the Andals, the Rhoynar, and the First Men sat, located in the Great Hall of the Red Keep in the city of King's Landing. Besides the monarchs themselves, only their Hand could sit on the Iron Throne. The Iron Throne was also a metonym referring to the monarchy that rules the Seven Kingdoms and the authority of the monarchy (e.g. "rebellion against the Iron Throne").
The Throne was forged and ruled by the Targaryen dynasty from 1612 to 1998, during which time a devastating civil war of succession known as the Dance of Dragons broke out after the death of King Viserys I. The war began over long-standing WesterosI customs of male preference in inheritance, for Viserys I had only a single daughter Rhaenyra from his first marriage and named her his heir. Though after remarrying and having a son named Aegon, Rhaenyra‘s claim was usurped by her brother which started the war. The War cost the lives of both Queen Rhaenyra and her husband along with all but one Of her children, both sides also lost many of their dragons which ended in the species‘s century of extinction on Fratis.
The Targaryen dynasty was overthrown in 1998 in a rebellion led by Lord Robert Baratheon and forced the five year old Viserys Targaryen and his newborn sister Daenerys to flee from Dragonstone to Essos. The Baratheon dynasty ruled for nearly twenty years until the death of King Robert I. After which his two brothers Stannis and Renly laid claim to the throne along with Joffrey, though the latter was the oldest Of three illegimate incest children from Cersei Lannister and her brother Jaime. During the War of the Five Kings the three Baratheon claimants were dead with Joffrey’s brother Tommen committing suicide after his wife’s death , and subsequently the Throne was assumed by his mother the Queen Mother Cersei Lannister as the first official ruling Queen of the Seven Kingdoms. Though in reality her kingdom only includes the Lannister domain Of the Westerlands and the royally administered Crownlands around Kings Landing.
Daenerys Targaryen lays claim by right of blood on the throne and currently wages a war against Cersei to take the throne from her.