He is widely regarded as the greatest US President, one of the finest orators in history and the man who emancipated millions from slavery.

But as a previously unseen historic letter shows, when Abraham Lincoln was assassinated in 1865, his standing did not stop an amibitious mayor in sharing the condolences of the far-flung town of Thetford.

And 150 years on from 'Honest Abe's' death, Thetford is again helping to show the great man's importance by contributing to an historic exhibition.

Thetford's mayor, Sylvia Armes, has been asked to write a letter to the Abraham Lincoln Presidential Library reflecting on the former president's impact and ongoing influence on the town.

The letter will partner a letter from William Pike Salter, Thetford mayor in 1865.

Unbeknown to the town council, Mr Salter's letter has sat in the Presidential Library vaults for 150 years. When it was found by historians looking to mark the anniversary of Lincoln's death, Thetford was chosen as one of the town's which would contribute to the exhibition.

Mrs Armes said the news of Mr Salter's letter was a shock.

'They sent a copy of the original letter with their invitation for us to write something, and it was a real bombshell.

'To think that a letter from Thetford has been sat in the Presidential Library for all those years is amazing,' she said.

In writing a reply, the town's links to Thomas Paine provided an obvious reference point.

Mrs Armes worked with former mayor Stuart Wright, treasurer of the Thomas Paine Society, in writing the letter.

Mr Wright said his research showed that Lincoln would have been strongly influenced by Paine's work, with the Thetford-born writer dying in 1809.

'An essay by Lincoln on Paine was burned by his political agent as he said it might be bad for his career, so he was a clear influence.

'They both believed in God, but not the structure of the church, and they were controversial views at the time,' he said.

The letter will make up part of an exhibition at the Presidential Library, which is in Springfield, Illinois.

Lincoln died after being shot by John Wilkes Booth at Ford's Theatre in Washington DC on April 14.

• What do you think of the letter's discovery? Let us know by emailing tbw.letters@archant.co.uk