The Clementine Collection comprises the combined personal libraries belonging to the Albani family of Urbino and Rome. This noble Italian family included several cardinals, as well as Giovanni Francesco Albani who reigned as Pope Clement XI from 1700-1721. Strengths of the Collection include Roman and canon law, church history, philosophy, and a significant collection on Jansenism, with considerable unique material pertaining to this movement, to the Gallican church of the 18th century, and to the aftermath of the bull Unigenitus. Also present are books of Italian literature and drama which are expected in a library of cultured men who were also important patrons of the arts. A number of these are significant as association copies, dedicated to Albani family members, especially Clement and his nephews, Cardinals Annibale and Alessandro Albani (the latter serving for some years as head of the Vatican Library). Books date from the 15th century to the early 19th. A preliminary analysis places over eleven percent of the imprints in the 16th century, with the largest percentage dating from the 17th and a slightly smaller number from the 18th century. Owing to frequent rearrangements of the materials and early studies of the collection by subject matter alone, no accurate picture exists of the collection's overall chronological breakdown. An estimated 30 percent of the books are not represented in OCLC, the cataloging database accessed by scholars via WorldCat.