period. In particular, Paul aimed to increase the flow of light in the Hall of Constantine. Ligorio, as his most trusted architect, was chosen to remedy the darkness problem. They chose to destroy the old papal apartment and incorporate a rooftop garden into the space, allowing more light to enter the Hall of Constantine. Towards the end of Paul IV's tenure, he asked Ligorio to design a monstrance, or tabernacle, to be used for special papal trips. It was to be stored in the newly designed chapel. Unfortunately, Paul died while the project was still in its early stages. The following pope, however, greatly valued continuation of unfinished projects, and ordered that Ligorio finish the monstrance. Upon completion, it was sent to Milan as a gift to the Duomo. Pope Pius IV (1559–1565) Pius IV rose to the papacy in 1559, already holding a reputation as a strong patron of the arts—architecture especially. In fact, within the first three years of his pontificate, he spent a million and a half gold scudi on building projects. His approach was unique in that he prioritized finishing incomplete projects, rather than starting new ones. This aligned well with Ligorio's values, specifically his desire to restore fragmented artifacts and preserve classical antiquities. Under Pius IV, Ligorio was once again paired with his assistant, Sallustio Peruzzi. Their first major project was remodeling the Vatican Library in 1560. Some records suggest plans to create an entirely new library, but due to lack of funding, these updates likely involved smaller-scale woodworking and masonry by Ligorio. He was also tasked with smaller projects in this time, such as masonry work and apartment building throughout the palace. In May 1560, Ligorio received a commission of great significance: the continuation of Paul's plans for the papal casino. Located in the woods behind the Belvedere court, Pius' revamped plans for the space included a second story, large fountain, and oval courtyard with arched entryways. The decorations matched Ligorio's preferred Raphaelesqu style. It was named the Casino of Pius IV in honor of the pope who supported its construction. Swiss historian Jacob Burckhardt called it "the most beautiful afternoon retreat that modern architecture has created." On 2 December 1560, Ligorio was awarded with honorary Roman citizenship for his contributions to the culture and architecture of the city. This was a major honor, awarded to only three other people during the sixteenth century: