A collection of almost 1,000 17th-century pamphlets covering the English Civil War, the restoration of Charles II, and freaks of nature such as lion-shaped comets, will today be presented by the Home Office to the British Library.

The Home Office has no idea how it came by the pamphlets, bound up into 17 volumes, but thinks it has owned them for at least a century.

At the library, curator Giles Mandelbrote has been poring over them. The signatures of four people recur on different pamphlets: he has already traced several distinguished 17th-century lawyers, including Sir Edward Northey, who ended up as attorney general.

Mr Mandelbrote believes the pamphlets represent the collections of several different people, bound up by a later owner. He suspects a royalist source, particularly since many were printed in the royalist stronghold of Oxford.

Many are now very rare, and several are unique - and the rather grand owners he has traced are also a puzzle because the bindings were the cheapest of their day.