WINDAU in German but VENTSPILS was the Russian name from the time of the Russian Empire,

 ВУНДАЕА, ВУНДАЙ although ВЕНТСПИЛС, a transliteration of VENTSPILS has been used since WW II.

 Some other names for the city include Livonian VANTA and Polish WINDAVA. Ventspils is a city in North  Western Latvia in the historical Courland region of Latvia, and is the sixth largest city in the country. It is situated on the Venta River and the Baltic Sea, and has an ice-free port.

 The city's name means "castle on the Venta", referring to the Livonian Order's castle built on the Venta River.

 Old Ventspils was devastated by 18th-century wars and plague, its importance dwindled until it was annexed by Russia in 1795. The Russians saw little use for Ventspils port for a long time and by 1863 Ventspils had  merely 4000 inhabitants, some 50% of them the descendants of Courland-Semigallia’s German elite. The tides of fortune turned again in the 1890s, as the railway from Riga reached Ventspils, allowing the port to be used to export goods from the entire Russian Empire. An era of rapid expansion followed, during which the city grew to 29000 inhabitants as it needed to staff the swiftly growing port.   The port played an important role in the export of flax and hemp products to the UK in the 18th/19th centuries .. and today is an important oil terminal.