Palazzo Solia, also known as Palazzo Boniface VIII, was built on the orders of Pope Boniface VIII, according to some historians. Others believe a more likely version that the palace was built by the inhabitants of Orvieto, in gratitude to this Pope, who took the city from the papal interdict and a huge fine for the damage caused by the troops of the castle town in the valley of Val di Lago. To this day, the Palazzo Solia remains the property of the Catholic Church.

A wide staircase leads to the second floor in the most spacious room of the palace with ten Gothic windows, which was used as a reception hall for officials. This floor was built between 1296 and 1297 years of the covered gallery of the first floor, the construction of which began when Pope Urbana IV. The top of the palace is topped with battlements Guelph and is decorated with a number of windows, divided into two columns of the arches.

Today in the Museum of Palazzo Solia works of art from the Cathedral of Orvieto (Museo dell'Opera del Duomo). It preserves works from the Renaissance to the era of Mannerism and the painting in the 19th century. Among the artists whose works are represented in the museum - Giovanni Lanfranco, Girolamo Mutsiano Federico Dzukkaro, Cesare Nebbia, Pomarance. Of particular note is a priceless collection of paintings and drawings by Ippolito Scalzo Cesare Nebbia frescoes on the alteration of the Cathedral. Mannerist sculpture apostles and saints that adorned the cathedral until the 19th century, are also part of the museum's collection.

At the bottom of the Palazzo Solia running another museum - the Museum of Greco, dedicated to an artist who worked on the great doors of the Cathedral of Orvieto. Here you can see about a hundred of his works.