Pentos is one of the nine Free Cities of Easteros. It is one of the wealthiest and most prosperous cities of Easteros, deriving much of its power and wealth from its geographical landscape. Pentos is a port city and engages in trade and commerce with much of the rest of the world. It is also one of the most populous cities of Easteros, though as one of the Free Cities, slavery is outlawed.

Pentos is technically ruled by an elected prince, though the governing power of the city actually rests amongst the council of magisters. One of the most powerful and prosperous of these magisters is Illyrio Mopatis. Illyrio Mopatis hosted Khaleesi and her brother, Viserys, at his palace in Pentos at the onset of Season 1. Today, Varys and Tyrion have sought refuge at this same palace.

Illyrio Mopatis, hosting Khaleesi and her brother at his palace in Pentos

Pentos was originally conquered by the Valyrians hundreds of years ago and established as a trading outpost during the expansion of the Valyrian Freehold.