Formerly known as the Ile du Palais, the Ile de la Cité is the cradle of Paris. In the 12th century, it was regarded as “the head, heart and marrow of Paris”. Located on the Seine, between the Marais district on the right bank and the Latin Quarter on the left bank, the island covers 22.5 hectares. From the Carolingian era until the end of the Middle Ages, the island was the seat of royal and episcopal power. Between the 12th and 14th centuries, the Notre-Dame Cathedral and the Sainte-Chapelle were built there. The latter was intended to house precious relics of Christianity – including the Crown of Thorns of Christ – acquired by Saint Louis.