Located within Siena's Cathedral, the Piccolomini Library houses dozens of Pope Enea Silvio Piccolomini's beautifully ornate illuminated manuscripts. The library itself was painted by Preguian painter Pintoricchio in 1502 for the cardinal of Siena, his patron, in order to honor his uncle Pope Pius II who died in 1464. The frescoes on the walls and ceiling tell the mythologizedand glorified story of Pope Pius's life with surrounding decorative elements, as are seen the photograph. Throughout his career, Pintoricchio was known for painting paritcularly bright and decorative patterns, colors, and costumes.
From a non-expert perspective, the Piccolomini Library is one of the more unique sights in Siena, full of beautifully decorated anthem books (on a side note, one can also find more of Piccolomini's anthem books in the Museo dell'Opera di Duomo). During the tourist season, meaning from about March 1 through the summer, the cost of the Duomo (€4) includes admission into the library. Definitely a sight worth seeing if one when one visits Siena's beautiful cathedral.