In the letter Oliver Cromwell recommends a captain for promotion
A letter from 17th Century anti-monarchist statesman Oliver Cromwell has been found at a council premises.
The Cambridgeshire-born MP led a rebellion which saw the monarchy overthrown and England become a republic between 1649 and 1660.
This year marks 350 years since Cromwell's death.
When a volume of letters was cleaned at Essex County Council's record office, workers found the historic note.
The volume originally belonged to the Rev Philip Moran, an Essex historian whose collection of papers and notes is looked after by the council.
In the letter, dated 25 March 1642, Cromwell recommends Captain Dodsworth for promotion, whom he describes as an "honest, religious and valiant gentleman".
Jeremy Lucas, of Essex County Council said: "This is an incredible find. We are delighted to have found such a well-preserved window into our past."
The letter can be viewed at the record office.