Which preposition to use with valdemar

at Occurrences 1%

He himself was killed, and Valdemar at last was King of all Denmark.

to Occurrences 1%

During the Folkung Dynasty, in the fourteenth century, the royal houses of Sweden and Norway became united through the marriage of Duke Eric, of Sweden, and Ingeborg, only child of King Haakon, of Norway; and Duke Valdemar to the king's niece of the same name.

Which preposition to use with  valdemar