Radviliskis is a city in the Radviliškis district municipality , Šiauliai County, Lithuania. Radviliskis has been the administrative center of the district since 1950, and is an important railway junction. Radviliskis was founded at the end of the 15th century. It was first mentioned in the book on state economics by M. Downar-Zapolsky listing the cities taxpayers in 1567. In 1687, Jan Sobieski, the king of Lithuania and Poland, granted the right of holding a market to it. Town growth began when the Liepāja–Romny railway line, crossing the town, was built in 1870 and Radviliškis–Daugavpils line was built in 1873. Railwaymen constituted the majority of the residents.