Many of the letters were copied out by Pepys’s secretaries, in particular by his clerk William Hewer (1642-1715). The letterbook does contain some that were hand-written by Pepys and also some in the same shorthand he used to write his diary. This type of shorthand known as ‘tachygraphy’ was developed by Thomas Skelton in 1641. Pepys held two significant administrative positions during the years covered in the letterbook: as clerk of the acts from 1660 and as secretary to the Admiralty from 1673. Included is a letter written at the time of the plague when the Navy Board retreats to Greenwich. The letter, written by Pepys in shorthand on 28 September 1665, relates to the fitting out of the fleet for the next year.