Danes () are the citizens of Denmark, most of whom speak Danish and consider themselves to be of Danish ethnicity. The first mention of Danes within the Danish territory is on the Jelling Rune Stone which mentions how Harald Bluetooth converted the Danes to Christianity in the 10th century. Denmark has been continuously inhabited since this period; and, although much cultural and ethnic influence and immigration from all over the world has entered Denmark since then, Danes tend to see themselves as ethnic descendents of the early Danes mentioned in the sources. Since the formulation of a Danish national identity in the 19th century, the defining criteria for being Danish has been speaking the Danish language and identifying Denmark as a homeland. Danish national identity was built on a basis of peasant culture and Lutheran theology, theologian N. F. S. Grundtvig and his popular movement played a prominent part in the process. Today, the main criterion for being considered a Dane is having Danish citizenship. However, other criteria include people with a Danish ancestral or ethnic identity; people living outside of Denmark such as emigrants; and descendants of emigrants or members of the Danish ethnic minority in Southern Schleswig, Germany can be considered Danes under a wider definition taking into consideration cultural self-identification.