When Antonio (later Sir Anthony) Panizzi was promoted from Keeper of the Department of Printed Books to Principal Librarian (i.e. Director) of the British Museum in 1856, the role of the British Museum Library as the national library (in fact, although not in theory) had been established. This was the result of his work as Keeper since 1837, and of the work of Sir Frederic Madden as Keeper of Manuscripts since the same date. Although he kept a close eye on his old department, Panizzi had to spend much of his time during his ten years as Principal Librarian dealing with the antiquities and natural history departments of the Museum, and with the accommodation problems of the institution as a whole. He also improved the morale of the staff by obtaining for them in 1860 the benefit of retirement pensions. This had the additional advantage of increasing the efficiency of the Museum, because hitherto the Trustees had been reluctant to dispense with staff who were past their best, because of the financial hardship which this involved.

John Winter Jones, who succeeded Panizzi as Keeper of Printed Books (and in 1866 followed him as Principal Librarian), was his devoted disciple and had every intention of continuing on the lines which Panizzi had laid down. So he successfully campaigned for the restoration of the purchase grant for printed books to the figure of £10,000 per annum which Panizzi had achieved in 1846 (and which had been cut in the 1850s, because of the lack of space to house books until the new Reading Room and Iron Library were completed in 1857).