St Mary's Church (Mariakirken) was the royal chapel and had an important political role, as its provost from 1314 also was Chancellor of Norway. It was built originally in 1050 AD, but rebuilt and expanded several times. Final additions made in the 1300s. In the beginning of the 14th century, it was the third largest church in the country, and in the Middle Ages it was the royal chapel. The church was set on fire by Swedish forces in connection with an attack in 1523. After the Reformation, it was so dilapidated that it could not be repaired and was demolished in 1542.
Excavations were first conducted in 1867 under Nicolay Nicolaysen and later in the 1960s under the leadership of Håkon Christie. Remains of two people, deemed to be King Haakon V (1270-1319) and his Queen consort Euphemia of Rügen, were discovered during excavations of the ruins of the church and reinterred in the Royal Mausoleum in Akershus Castle.
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La Hougue Bie is a Neolithic ritual site which was in use around 3500 BC. Hougue is a Jèrriais/Norman language word meaning a \'mound\' and comes from the Old Norse word haugr. The site consists of 18.6m long passage chamber covered by a 12.2m high mound. The site was first excavated in 1925 by the Société Jersiaise. Fragments of twenty vase supports were found along with the scattered remains of at least eight individuals. Gravegoods, mostly pottery, were also present. At some time in the past, the site had evidently been entered and ransacked.
In Western Europe, it is one of the largest and best preserved passage graves and the most impressive and best preserved monument of Armorican Passage Grave group. Although they are termed \'passage graves\', they were ceremonial sites, whose function was more similar to churches or cathedrals, where burials were incidental.