On opening in 1900, the library had 70,000 books and fewer than 100 manuscripts and by 2012, more than 250,000 printed volumes and over one million manuscripts and archival items. The main foundation of the library's collections acquired in 1892 was the "Althorp Library" of Lord Spencer regarded as one of the finest library collections in private ownership with 43,000 items - 3,000 of which originate from before 1501 (i.e. incunabula). Mrs Rylands paid £210,000 for Spencer's collection which included the Aldine Collection and an incunabula collection of 3,000 items. The incunabula included a few blockbooks and the St Christopher blockprint (southern Germany, 1423) the latter being the earliest dated blockprint whose date in undisputed. During subsequent years more than 1,000 more incunabula wre added to the collection (from various sources).