Church of the Cross was a small medieval parish church for the northern part of the Old Town of Oslo. The ruin was rediscovered in 1922 and is now a part of the Ruin Park containing the ruins of the church and the greater St. Hallvard's Cathedral.
There is no definite information about when the church was built. The church is not mentioned in the sources of the fighting in Oslo in 1240 between King Haakon IV and Duke Skule, suggesting that it is possibly younger. In 1989 it was found a stick with runic inscriptions, dated to the first half of the 1200s. The name Church of the Cross occurs in this inscriptions, and it indicates that it may be older than 1240. When the church was built, it was located far north in the city, and an urban development north of the church came in the second half of the 1200s and the 1300s.
Church of the Cross had input from the west, from the cemetery, an entrance from the west and an entrance directly to the chancel from the south. The remains of the original altar foundation is visible. Around the church are the remains of the cemetery wall.References:
The Basilica of Santa Maria in Trastevere is one of the oldest churches of Rome. The basic floor plan and wall structure of the church date back to the 340s, and much of the structure to 1140-43. The first sanctuary was built in 221 and 227 by Pope Callixtus I and later completed by Pope Julius I.
The inscription on the episcopal throne states that this is the first church in Rome dedicated to Mary, mother of Jesus, although some claim that privilege belongs to the Basilica di Santa Maria Maggiore. A Christian house-church was founded here about 220 by Pope Saint Callixtus I (217-222) on the site of the Taberna meritoria, a refuge for retired soldiers. The area was made available for Christian use by Emperor Alexander Severus when he settled a dispute between the Christians and tavern-keepers.
The church underwent two restorations in the fifth and eighth centuries and in 1140-43 it was re-erected on its old foundations under Pope Innocent II.