The 13th century was also a period of large-scale German immigration, during the "Ostsiedlung", often encouraged by the Přemyslid kings. The Germans populated towns and mining districts on the Bohemian periphery and in some cases formed German colonies in the interior of the Czech lands. Stříbro, Kutná Hora, Německý Brod (present-day Havlíčkův Brod), and Jihlava were important German settlements. The Germans brought their own code of law – the "" – which formed the basis of the later commercial law of Bohemia and Moravia. Marriages between Czech nobles and Germans soon became commonplace.