St. Hanshaugen
To the southeast of the park is Oslo’s oldest building – Aker Kirke, built around 1100, but restored from ruins around 1860, and then again in the 1950s in a more authentic style. Next to the church is the cemetery Vår Frelsers gravlund, created in 1808 as a result of the great famine and cholera epidemic of the Napoleonic Wars. The nearby area around Damstredet and Telthusbakken is interesting since it retains the small town character of Oslo in the first part of the 19th century.
Old Bishop's Palace in Oslo
The Old Bishop's Palace in Oslo ("Oslo Bispeborg") was the residence of the Roman Catholic bishops of Oslo. The estate is located in what is now called Gamlebyen (old town) in Oslo, Norway. Various remnants of the medieval bishop's original palace are still visible.
The construction was begun around 1210 by the then bishop, Nikolas Arnesson, continuing through to the early 14th century. The palace built in stone replaced a previous bishop's residence built in wood, established in the 12th century. The main buildings were surrounded by tall walls, and from a tower, a wooden bridge connected the palace to the neighboring Hallvards Cathedral. The palace was built like a fortified castle. 
Together with the cathedral, the palace was not only a religious centre in Middle Age Oslo, it was also of significant political importance. The first agreement of union between Norway and Sweden was signed in the bishop's palace just after the death of Håkon V of Norway, in 1319.