Who are the incas? and where did they also, how long did they exist?

The Incan Empire arose from the Peruvian mountains in about the 13th century.
The last were conquered by the Spanish in 1572.

So they were farmers in South eastern Peru, before they decided to expand, who lived in and around Peru and, at their peak, much of South America, and who ruled for about 300 years.

He would most likely post his laws in the city market