During the later part of 1687, the Corporation's activities widened even further as it gained the authority to examine potential pilots and to issue them with certificated licences. Trinity House had always had an interest in pilotage, but formal powers to examine these pilots came after Pepys' visit to Spain in 1684. He had been impressed by the Spanish system of examination, adopted by the 'Casa de Contracion', a Spanish authority for the management of trade to the Indies. This examination board consisted of Don Miguel Zuero (the Master map-maker of Spain), the 'Piloto Mayor', a distinguished member of the 'Universidad de Mercantes' (college of merchants), and six master pilots. Any aspiring pilots were publicly questioned on their knowledge of navigation and sea management. Only the best would achieve a certificate of competence and become pilots. This idea was readily accepted by James II and formally acknowledged in the Charter [Pepys,,Tangiers].
Trinity House was also authorised to fix its own rates of pilotage and, more importantly, to examine Masters for the Navy. This part of the Charter came up against a great deal opposition, especially from the 'land-based' politicians of the Admiralty Board, whose only thoughts were for lower overheads from sea-trade, no matter who commanded the ships.
On the 24th February 1696, Ambrose Marshall became the first recorded pilot to receive his licence. His documents, issued by Trinity House, allowed him to cover the area down the Thames as far as Gravesend.