With over 5,650 books, the earliest dating from the 16th century, Highclere's wonderful double library provides a fascinating insight in to daily life at the castle and has been used as a rich backdrop to several important scenes in Downton Abbey. During the late Victorian period, it was used by the 4th Earl of Carnarvon as a "withdrawing" room. The Earl was an active Tory in Parliament and a member of Disraeli's Cabinet in the 1860's and 1870's. In this library, he could discuss politics with friends or retire in peace. The red ground of the library’s carpet is of a rich madder, made using natural colours and dyes. Its design was developed during the reign of Shah Abbas I (1571-1629). King Abbas set up royal rug factories across Iran appointing the city of Isfahan as the capital. The carpet from the library at Highclere was made by 18th-century weavers from the city of Kashan.