The letters of 18th century evangelical revivalist George Whitefield are to be published for the first time.

Edited by historian Dr David Jones of Aberystwyth University and Dr Geordan Hammond of the Manchester Wesley Research Centre, the first volume will be published in 2018, with a further six volumes to be printed at a later date.

Born in Gloucester, Whitefield (1714-70) was an Anglican clergyman renowned for his charismatic preaching. After studying at Oxford University, where he was close to the Wesley brothers, he inspired a Protestant renewal movement; often preaching to large open-air crowds throughout Britain, and even across the Atlantic in America. He addressed some of the largest crowds ever recorded – often up to 30,000, and sometimes considerably more – as part of the Great Awakening that spread across Britain and the American colonies.

He is considered the mid-18th century's most famous and widely-travelled evangelical revivalist and became known as 'the apostle of the English Empire'. He was one of the founders of Methodism, and John Wesley preached at his funeral, on Whitefield's request.

The letters were written between 1735 and 1770, and are now located in Britain, North America and Germany.

Jones branded their publication "a major and exciting undertaking".

"The appearance of the letters in print for the first time has the potential not only to revolutionise understandings of Whitefield and the eighteenth-century evangelical and Methodist movements, but also the internal dynamics of the Atlantic World, and relations between Britain and America on the cusp of the Revolution," he said.