Planning and building of the Duchy of Courland and Semigallia cities, as well as architectural environment developed over many centuries affected by local traditions and culture other countries. In the Duchy of Courland and Semigallia, where Lutheranism was proclaimed as the official religion, urban centres formed near the Lutheran church and the Market Square. Network of streets and new types of building gradually developed. In 17th century political events in Europe determined Courland and Semigallia city’s future growth. Fortification building development was promoted, changing urban design and construction. The main objective of the study – to find out building spatial composition and planning functional solution of Coutland and Semigallia cities.