Notre Dame de Paris (French for "Our Lady of Paris"), also known as Notre Dame Cathedral or simply Notre Dame, is an historic Roman Catholic Marian cathedral on the eastern half of the Île de la Cité in the fourth arrondissement of Paris, France. Widely considered one of the finest examples of French Gothic architecture and among the most well-known churches ever built, Notre Dame is the cathedral of the Catholic Archdiocese of Paris; that is, it is the church that contains the cathedra (official chair) of the Archbishop of Paris, currently André Vingt-Trois. The cathedral treasury is notable for its reliquary, which houses the purported crown of thorns, a fragment of the True Cross and one of the Holy Nails – all instruments of the Passion and a few of the most important first-class relics. Notre Dame de Paris is often reputed to be one of the most prominent examples of Gothic architecture in both France and in Europe as a whole, and the naturalism of its sculptures and stained glass are in contrast with earlier Romanesque architecture. The first period of construction from 1163 into 1240s coincided with the musical experiments of the Notre Dame school.