Rosenborg Castle was built by King Christian IV in 1606-34 as a summer residence, and the next three generations of kings lived there until 1710, when Frederiksberg Castle was erected. After that Rosenborg was used only for occasional visits and as a sort of storehouse for royal family heirlooms. It also hosts the Treasury, where the crown jewels are displayed, which was the reason I wanted to hike way out to this castle. Just as we got there it started to rain again, but by the time we had finished touring it, the sun had come out.