David Hume, The History of England from the Invasion of Julius Cæar to the Revolution of 1688, New Edition, Chapter 50, paragraphs 57--66, and Chapter 51, paragraphs 1--47.

I have included here rather more than just Hume's description of the assasination of the Duke of Buckingham, with a view to providing some background, in particular to give some account of John Felton's motives, as well as the reason why the Duke of Buckingham was in Portsmouth.

This extract from Hume's History was scanned in from the edition printed by Harper and Row, New York, 1879, Volume IV, pp. 434--462. Hume's History was originally published 1754--1757, and the corrected edition quoted here was published in London, 1762.