In the 13th century the Holy Roman Empire became interested in the area populated by Balts. Ports and navigable rivers were used to occupy the coastal territories of the Baltic Sea. The Great war route (Hellweg) was created from Danzig (Gdansk) through Koenigsberg (Kaliningrad), Memel (Klaipeda), Palanga till Liva (Liepaja) and then trough Grobina, Aizpute, Goldingen (Kuldiga) and Tukums to Riga. The sovereign territories of Curonians and Semigallians were included in Livonian Order after signing a surrendering contract in the August of 1267. It became urgent to establish a new system of administrative political centers. In 13th century financially and economically independent strongholds were established at strategic locations on difficult-to-access islands or peninsulas to control sea ports and inland waterways, and protect borders. Locations of fortified castles and inhabited territories as well as waterway and road directions determined the planning composition, which influenced the further development of planning and building of city centers in western Latvia. The sovereign territories of Curonians and Semigallians were conquered in the 14th century. The establishment of administrative and political centers of Livonian Order were completed. The first cities were founded in the Western territory – Kuldiga, Aizpute, Ventspils, and Piltene who developed as a medieval agglomreation. Strongholds lost their function of providing refuge for local residents in case of a war and became feudal residences. The first manor houses were built in the territories surrounding the fortresses. The number of manor houses grew in the 15th century and the number of fortified dwellings was not increased anymore. The road network was improved. Building were developed in the areas adjacent to manor centers. A new type of residential buildings was created – a single-floor free-standing buildings with a tripartite symmetric layout with a chimney in the center and a hip roof. After the fortifications were liquidated, a radial planning developed in the cities. The tripartite residential buildings were suitable for placement next to streets and roads.