Pentos

Pentos is one of the Free Cities located on the north-western coastline of Essos, across the Narrow Sea to the east of Westeros. It is a large, rich city and is the home of Magister Illyrio Mopatis. Daenerys and Viserys Targaryen are temporarily resident in Pentos when the series begins.

In the books
Pentos was the northern-most of the large Valyrian colony-cities when the Doom destroyed the empire five centuries ago. Pentos and the other Free Cities became independent over the course of the many-sided war known as the Bleeding Years. Pentos is a large seaport consisting of squat brick buildings and a number of large palaces and holdings, both within the walls and outside on the plains known as the Flatlands. The city is ruled by a prince, who is elected from the Council of Magisters, made up of the city's major merchant lords. Pentos has fallen under the influence of Braavos, the largest and most powerful of the Free Cities, and to maintain good relations with Braavos Pentos has outlawed slavery. Pentos's location makes it especially vulnerable to raids from the Dothraki. As such the Pentosi merchants are prone to feasting and gifting the passing Dothraki warlords with lavish parties and gifts to appease them into not destroying their holdings.