An offical certificate showing the four years and four months that Robert Oliver had served with the Royal Navy including the names of the ships he served on such as HMS FORMIDABLE; HMS MARS; HMS GELYKHEID; HMS RUBY; HMS EAGLE; HMS FLINT and added for 1807 HMS ROYAL SOVERIGN.

Administrative / biographical background
The PRINS FREDERIK WILLEM was a Dutch 68-gun third rate ship of the line of the navy of the Dutch Republic, the Batavian Navy, and the Royal Navy. In 1795, the ship was renamed GELYKHEID (Equality). On 11 October 1797 the the ship took part in the Battle of Camperdown were she was captured by the British and renamed HMS GELYKHEID. In 1799, the HMS GELYKHEID was a prison ship at Chatham and in November 1803 the ship was stationed in the Humber as a guardship.