Captain Tyler and his wife Margaret, daughter of Abraham Leach of Pembroke bought Underdown in 1788 and moved in immediately after their marriage in St Mary's church Pembroke. He was 28 and she was 29. They renamed the house Northdown House and made many changes and alterations, probably adding the whole of the front wing. Here he and Margaret had five children.
In 1805, Captain Tyler commanded HMS Torrant at the Battle of Trafalgar, and was severely wounded in the thigh. He was retired on a pension of 250 pounds per annum but later returned to the navy and became Admiral Sir Charles Tyler, GCB, Admiral of the White. He knew Lord Nelson very well, both having been born in Norfolk- Nelson in 1758 and Charles in 1760- and both going to sea as boys, Charles in 1771, at the tender age of 11; Nelson in 1773 at fifteen. Charles and Margarets first son, born here in 1792, also followed him into the navy, later becoming Vice Admiral Sir George Tyler, lieutenant governor of the island of St Vincent, 1833-40.
Sir Charles went to sea at the tender age of eleven and was only a midshipman of sixteen when his ship took part in the 'Boston Tea Party' of 1766- where America gained its independence. His father was a captain in the army and fought at the battle of Bunker Hill when Britains colony of North America first began its fight for freedom.
In 1817, after 29 years here, Sir Charles and lady Margaret moved to Glamorganshire. She died in July 1835 at the age of 76 and he followed her six weeks later, aged 75.
