Shrewsbury's Oxfam Bookshop received the 1600s copy of Varia Opuscula Theologica by Doctoris Francisco Suarez from a local donor.

It is listed on the rare books website, Abe Books, with a price of about £500.

Suarez was a Spanish Jesuit and he is considered one of the most important scholastic theologians of his age.

Written in Latin, the book contains the writings of Suarez which were forbidden by Pope Innocent XI in 1679 and ordered to be burned. The book contains a stamp which shows it was originally held in a Rome library.

Tom Cotton, manager of the Oxfam Bookshop in Dogpole, said the book is considered extremely rare.

He said: "All of his books were burned and this is a pre-burning copy. It is in Latin and is very obscure. It looks like it came from one of the famous Catholic colleges in Rome."

Mr Cotton said that he had called on a former volunteer at the shop to help him identify where the book was from.

He said: "We had to get an old volunteer back who was used to dealing with antiquarian books and could look at the value and come up with a description for it.

"He is very good at being a detective for books."

The shop is no stranger to rare books and Mr Cotton said he believed the most valuable book it had received was a first edition signed copy of To Kill a Mockingbird, which sold for £800.