Postal history of Latvia started in the 13rd. century when Archbishopic of Riga started its service for government purposes. During World War 1, Latvia was occupied by the Germans and used German stamps overprinted by the Ober Ost. In 1919, German stamps were handstamped " Libau " but it was unclear whether they were officially issued as all used copies are cancelled to order. Latvia proclaimed its independence on 18 November 1918 and issued its first stamps on 18 December. The design was a depiction of the country's Coat of Arms. Latvia issued a variety of definitive and commemorative stamps throughout 1920s and 1930s. Definitives used variations on designs featuring the arms surmounted by three stars representing Vidzeme, Courland and Latgale. As part of the Soviet occupation in 1940, a series of 13 stamps were issued.