Gamle Aker Kirke (Old Aker Church) is Oslo's oldest remaining building and the only remaining church for the Middle Ages. It is assumed that it was built around the year 1150. It is a stone church, built as a three-naved Roman-style basilica. The church has been pillaged and ravaged by fire several times. The oldest part of the surrounding churchyard dates back to the 12th century, and it is said that the church is built over an old silver mine.