Researching Lord Seymour

The younger son of Edward Seymour, 1st Duke of Somerset by his second wife Anne Stanhope, he married Lady Joan (or Jane) Percy, daughter of Thomas Percy, 7th Earl of Northumberland.

In 1588, he was appointed Admiral of the Narrow Seas and took command of HMS Rainbow and the Squadron of ships that took part in the Battle of Gravelines against the Spanish Armada in 1588. Controlling the seas off Dunkirk they joined the main British fleet (the 'Western Squadron') near Calais on 6 August, adding about a third to the total size.

Seymour maintained a reputation as a courageous and innovative officer: he was awarded a commemorative medal for his actions at the battle of the Glorious First of June and is credited with introducing epaulettes to Royal Navy uniforms as a method of indicating rank to non-English speaking allies. In his youth he formed close personal friendships with fellow officer John Willett Payne and George, Prince of Wales, through association with whom he gained a reputation as a rake. His marriage in 1785, made at the insistence of his family as an antidote to his dissolution, was brought about through royal connections and proved very successful. During his lifetime he also held several seats as a member of parliament in the Parliament of Great Britain, although he did not pursue an active political career.

Seymour-Conway was educated at Eton and Hertford College, Oxford, and took his MA from Merton College in 1767. He was first elected to the House of Commons in 1766 as Member for Coventry. He generally, though not always, voted with his uncle and namesake Henry Seymour Conway. After the 1768 election, when he and Andrew Archer defeated a challenge by Walter Waring, he was a consistent supporter of the Grafton and then the North governments.

Due to a falling-out between his father, the Earl of Hertford, and the Corporation of Coventry, Seymour-Conway did not stand as a candidate there at the 1774 election. He was instead returned by the North administration at Midhurst, which was a Treasury borough that year. In 1776, he was also returned to the Parliament of Ireland for Antrim County, which he represented until 1783. As his re-election in Midhurst did not appear to be sustainable in the 1780 election, he stood successfully at Downton. In the 1784 election, Seymour-Conway and Robert Shafto faced off against Hon. Edward Bouverie and William Scott, and, a double return being made, the case came before the House of Commons. Seymour-Conway chose not to stand in the ensuing by-election; his brother William took his place and won the by-election. During this period, he was for some time a captain in the Warwickshire Militia, and befriended the poet George Crabbe while quartered at Aldeburgh. On 11 February 1793, he was promoted major.

The election of 1784 marked Henry's retirement from politics. In 1790, he and his brother Robert were jointly granted, for life, the sinecures of joint prothonotary, clerk of the crown, filazer, and keeper of the declarations of the King's Bench in Ireland. By 1816, these offices brought an income of more than £10,000 a year (equivalent to £ as of ) . He was also craner and wharfinger of the Port of Dublin, a sinecure abolished in 1830.

He spent the rest of his life in the improvement of his estate at Norris Castle, in the Isle of Wight, where he experimented with the use of seaweed as a fertiliser. He had a reputation for both eccentricity and benevolence when he died, unmarried, in 1830. There is a memorial to him in St. Mildred's Church, Whippingham. He left Norris Castle to his youngest brother Lord George Seymour, who sold it to newspaperman Robert Bell in 1839.

A member of the Seymour family headed by the Duke of Somerset, Seymour was the seventh son and youngest child of Francis Seymour-Conway, 1st Marquess of Hertford, and Lady Isabella, daughter of Charles FitzRoy, 2nd Duke of Grafton. He was the brother of Francis Ingram-Seymour-Conway, 2nd Marquess of Hertford, Lord Henry Seymour, Lord Robert Seymour, Lord Hugh Seymour and Lord William Seymour.

He was returned to the Parliament of Great Britain as one of two representatives for Orford in 1784, a seat he held until 1790. He later represented Totnes between 1796 and 1801.

Seymour married Isabella, daughter of Reverend the Honourable George Hamilton, in 1795. Their son Sir George Hamilton Seymour was a diplomat. Seymour died on 10 March 1848, aged 84, and is buried in St. Andrew's Church, Waterloo Street Hove in Sussex