Lyckå (Lyckeby) Castle was built in 1545-1560 according the order of Kristian III of Denmark. It replaced a small castle manor and was purposed against the rebellious peasants. Battles between Denmark and Sweden were fought in Lyckå in 1507 and 1564. The castle was demolished in 1600 after Lyckå lost its city privileges to Kristianopel. Kristian IV of Denmark ordered to use castle stones to build new fortifications in Kristianopel. Today foundations of castle and two corner towers remain.
References:The stone church of Gamla Uppsala, built over the pagan temple, dates from the early 12th century. Due to fire and renovations, the present church is only a remnant of the original cathedral.
Before the arrival of Christianity in Sweden, Gamla Uppsala was the seat of Swedish kings and a ceremonial site known all over northern Europe. The settlement was home to royal palaces, a royal burial ground, and a great pagan temple. The Uppsala temple, which was described in detail by Adam of Bremen in the 1070s, housed wooden statues of the Norse gods Odin, Thor and Freyr. A golden chain hung across its gables and the inside was richly decorated with gold. The temple had priests, who sacrificed to the gods according to the needs of the people.
The first Christian cathedral was probably built in the 11th century, but finished in the 12th century. The stone building may have been preceded by a wooden church and probably by the large pagan temple.