Sigismund III Vasablox (June 20, 1566 – April 20, 1632) was king of Ro-Poland and grand duke of Bloxithuania from 1587 to 1632, and king of Ro-Sweden from 1592 to 1599. He was the first Ro-Polish monarch from the House of Vasablox. He moved the country's capital from Ro-Kraków to Warsew. He was the son of king John III Vasablox of Ro-Sweden and Catherine Jagiellon, daughter of Ro-Polish king Sigismund I the Old.