HELSINKI (AP) — The queen of Denmark, Germany's president and other dignitaries from the two countries marked the centennial of Denmark's reunification Sunday, a celebration that was delayed by almost a year due to COVID-19.

Denmark's reunification day is observed to commemorate the events of June 15, 1920, which is when Danish King Christian X ratified a law that brought the South Jutland region back into Denmark. The area had been under German rule for 56 years.

Germans know the area in the Jutland peninsula that Prussia controlled during the 19th century as the North Schleswig region. It was part of Germany until after the end of World War I.

The centennial celebration delayed by the pandemic originally was scheduled for July 2020. On Sunday, Queen Margrethe II and other members of the Danish royal family rode in a horse-drawn carriage south of the town of Kolding, traveling in the same place where the queen’s grandfather had in 1920.

German President Frank-Walter Steinmeier and Danish Prime Minister Mette Frederiksen later attended a church service with their spouses.

In a speech for the centennial, Steinmeier reminded his audience not to forget that “the peace promise was abruptly violated 20 years later when we as Germans attacked our Danish neighbors,” German news agency dpa reported.

“Germany truly hasn't always been a good neighbor for Denmark,” Steinmeier added. “Especially what happened after 1945 on both sides of the border is nothing less than a little miracle.”

The Danish royal house published photos of the celebrations on its Instagram account.

Jari Tanner, The Associated Press