Cambridge University Library has one of five known sets of proof maps prepared for John Speed's Theatre of the Empire of Great Britaine (Atlas.2.61.1), which was published in 1611/12.
The maps were printed from copper plates which had been engraved, in reverse, by Jodocus Hondius in his workshop in Amsterdam. Maps printed from the plates - proofs - would have been sent back to England for checking.
The maps in Cambridge University Library's set of proofs are in a late state of preparation, but many were altered before being published. The map of Cheshire, which had been produced as early as 1603 by English engraver William Rogers, was completely replaced following the death of Rogers in 1604.
All 66 maps are now viewable in the Cambridge Digital Library
Images are available for download for non-comercial purposes (licensed under a Creative Commons Attribution-NonCommercial 3.0 Unported License (CC-BY-NC 3.0))
Image credit: extract of Ely from Speed's Huntingdonshire Atlas.2.61.1