Between 1180 and 1220 the French king Philip Augustus built the castle of the Louvre as part of a massive city wall. (Parts of the wall can still be seen in the Marais district behind the Hotel de Sens and near the Church of St.-Etienne-du-Monte.) The castle of the Louvre was a secure place to house the royal treasure and archives. The great toweróa round central towerówas over one hundred feet high and sixty feet in diameter, with walls twelve to thirteen feet thick. (Today the base of the tower forms part of the underground entrance to the Louvre Museum.) The tower stood in a rectangular court, surrounded by curtain walls with corner towers. Towered gates opened in the center of the south and east walls. In the fourteenth century Charles V added more residential accommodations, and in 1527 Francis I destroyed the medieval towers and walls to build a Renaissance royal palace and gardens.