Seymour was born at Preshute, Wiltshire, into a cadet branch of the Seymour family. He grew up at Marlborough Castle and inherited considerable estates in Wiltshire.
In April 1676 Somerset was in Paris, where he was received with great pomp and ceremony by the English ambassador, John Berkeley, Baron Berkeley of Stratton.
The secretary of state, Henry Coventry‡, informed the consul in Genoa, George Legatt, on 20 May 1678 that Charles II was ‘obliged not only in justice, but by many of the important considerations to show his resentment’. The king appeared genuinely angry and Legatt was instructed to convey the ‘great indignation’ he felt at ‘so horrible a deed done on a person of such high rank and quality’. The Genoese authorities pronounced the death sentence against Botti, but he evaded capture and was only hanged in effigy. James II later agreed to pardon Botti and dissatisfaction at this outcome was said to have been the reason why the 6th duke of Somerset snubbed the papal nuncio at the English court in 1687.
