The Mr Pepys of the title refers to the 17th century diarist and all-round extraordinarily talented man Samuel Pepys, and the piece tries to evoke something of the mood of his time.  The word "Pavan" is an alternative word for "Pavane", which was a slow and stately dance popular in the 16th and 17th centuries, the only difference being that "Pavane" is a French word and emphasises the second syllable, while "Pavan" emphasises the first syllable and sounds more English.  Since Samuel Pepys was very English, I chose "Pavan".
The piece is published along with its companion piece "Mr Pepys' Pleasure", both of which also appear in short versions.

Mr Pepys' Pavan harp duet (extended version)

STWD