Frederick IV of Denmark

king of Denmark and Norway (1699–1730)

Ertholmene (formerly spelled Ærtholmene) is a small archipelago in Denmark. The largest island is Christiansø, whose name is often used with reference to the entire archipelago. Ertholmene are situated northeast of Gudhjem, Bornholm, and include Denmark's easternmost point. Two of the islands, Christiansø and Frederiksø, are inhabited, with a combined permanent population () of 90. The archipelago has a total area of . Its name is derived from the Danish for "pea islands".

series of sieges of Stralsund between 1711 and 1715