Patan Durbar square was once the palace square and residence of the Malla rulers of Patan state in Nepal during 1900 BC. During that time, and currently Patan was known as Lalitpur city.
Patan Durbar square is one of three in Nepal. The others are Kathmandu Durbar Square and Baktaphur Durbar Square. The Patan Kumari is in resicence close to Patan Durbar Square.
Read more in this guide to Patan, Nepal.