Stjärnorp manor ruins are ruins of a 17th-century manor of the northern shore of Lake Roxen. The manor burned down in 1789 and the main building was never restored. Stjärnorp's castle was erected in 1655–1662 (in the parish of Vreta monastery ) by the Count and Field Marshal Robert Douglas (1611–1662). The castle and terraces were designed by Nicodemus Tessin. According to a story, it is said that when the war comrades and arms brothers Robert Douglas and Axel Lillie came home from the Westphalian peace, they entered into an agreement to build their respective castles, Stjärnorp's castle and Löfstad castle, so high that they could see and send greetings from the top floor to each other. All buildings were destroyed by a fire on May 12, 1789, but the castle chapel was restored already that year. The wing buildings were also rebuilt soon but financial resources were lacking for the main building, which is still a ruin. https://visitlinkoping.se/en/do/attractions/castles-and-manors/stj%C3%A4rnorps-slottsruin

Merlo Castle, or Villa Merlo, as it's really called, was built to serve as a summer residence for the mighty Bünsow, and did it until his death in 1897. Today you will find SCA's central archive here. http://guide.visitsundsvall.se/sv/se-gora/a1466172/merlo-slott/detaljer?filter=c%3D1578

King Kristian of Denmark loved building and commissioned many cities, castles and fortifications to be built around his kingdom including Halmstad Castle. https://www.destinationhalmstad.se/english/to-do/attractions.html?url=113685985%2Fdefault.aspx%3Fc%3D3%26TLp%3D641182%26TLl%3Den&sv.url=12.562a806313e8e51ee2e8bc7

The oldest parts of Linköping Castle stems from the 1100s and the castle is the oldest secular building in Sweden. Large parts of Linkoping burned down in 1700, including the town hall. http://visitlinkoping.se/index.php/en/castles-and-manors/link%C3%B6pings-slott