Sonderborg Castle

A castle has stood on this point above the Als sound since the twelfth century, guarding the crossing, and the building was remodelled repeatedly, most substantially in the 1720s when it was rebuilt as a baroque palace in yellow render around a courtyard, which is broadly what stands today. Christian II was held here for seventeen years in the sixteenth century. The chapel of 1568 survives as one of the earliest purpose-built Protestant church interiors in the world, largely unaltered, with its original fittings and gallery. The castle now houses the museum of southern Jutland, covering the region's long and complicated history, its shifting frontier, and daily life on Als, with the sound and the bridges visible from the windows.

History

Sønderborg, "southern fortress", probably began as a fortified tower built by Valdemar the Great in 1158 on an islet in the Als Sound, later joined to Als, as part of a system of defences against the Wends. Ownership of Als and the castle passed back and forth in the long struggle between the Danish king and the dukes of Schleswig, and Valdemar IV married Helvig of Schleswig here. Around 1350 the Blue Tower and great outer walls were added; the crown took the fortress in 1490, and Kings Hans and Christian II made it one of the strongest in the country. Christian II himself was held here as a prisoner of state for seventeen years, from 1532 to 1549, though in reality he lived in comparative comfort. Christian III had Hercules von Oberberg rebuild it as a four-wing castle in 1549-57, and Oberberg built the chapel in 1568-1570 for the Queen Mother Dorothea. From 1571 it was the centre of the small duchy of Schleswig-Holstein-Sonderburg, it returned to the Danish crown in 1667, and Frederick IV had it rebuilt in Baroque style in 1718-1726 by Wilhelm von Platen; the Blue Tower was pulled down in 1755 (Wikipedia, Sønderborg Castle).

What's there

• The 1568 chapel - among the earliest surviving purpose-built Protestant interiors.
• The baroque courtyard block - the 1720s rebuild in yellow render.
• The regional museum - southern Jutland's history across many rooms.
• The Als sound - the crossing the castle was built to control.

When to go

April to October for full opening; winter hours are reduced. Two to three hours. Weekday mornings are quiet. The waterfront outside is a good walk in any season.

What to expect

The museum is large and largely regional, with much of the labelling in Danish and German rather than English. The castle has been rebuilt so often that little medieval fabric shows. Winter opening is limited.

Nearby

Grasten Palace is west on the mainland; the Als coast runs north.

Key facts