The Johannine Empire, also known as the Danish Empire or Nordic Empire, was a mighty central and Northern European state in the 11th and 12th centuries. At its zenith in 1121, when Johannes IV was crowned, the Danish dominions stretched from northern Scandinavia to Rome, and included parts of the old Frankish kingdom and modern-day Angeland and Nordumber. The Johannine Empire was responsible for the mass Christianization of the Norse, the subjugation of Catholic states such as Hebernland, Caledonia and France, the repelling of Turkish forces from Byzantina, the establishment of a centralized German state, and the militarization of Europe in advance of the Mongol invasions of the 12th century.