The secrets of Bristol's greatest churchmen have finally been deciphered.

Charles Wesley, the co-founder of Methodism, left over 1,000 pages of coded journals. Much of this work was written when he lived in Bristol between 1749 and 1771.

After nine years of patient decoding, Rev Professor Kenneth Newport, pro vice-chancellor of Liverpool Hope University, has deciphered the secrets of the journals.

They could have been written today. They reveal that Charles was fearful of a growing split within the Church of England.

The Methodist Societies were started by Charles and his brother John within the Church of England. The Wesley brothers were both Anglican priests, but John had set a split in motion by ordaining priests to Methodism. The journals show that Charles was strongly opposed to his brother's actions, and to a formal split of Methodism from the church.

The journals also show that Charles was troubled by the "encroachment" of Islam into Western culture. At a more personal level he records his concern at his brother John's engagement to Grace Murray because she had once been engaged to another man.

Professor Newport highlighted the value of the journals as historical documents, showing issues of the time.

"This is a warts-and-all portrait of what was happening on the ground; it's the eerie privilege of peering over the shoulder of one long-dead and looking into their world," he said.

Charles Wesley was a prolific writer.

As well as the journals, he wrote more than 6,000 hymns, including the favourite Christmas carol Hark the Herald Angels Sing.

Much of Charles Wesley's journals is written in a personal shorthand.

The task was carried out by first translating his handwritten copy of the four gospels, also written in the same shorthand. This was then used as a guide to deciphering the journals themselves.

It was a painstaking puzzle, but professor Newport, an Anglican priest, said: "I was determined to unlock it. Charles was a great man, with insights that remain important for us today."

Charles Wesley first came to preach in Bristol in 1738, and he lived for over twenty years at 4 Charles Street in Bristol city centre. Charles's house can be visited by appointment.