Sir Thomas Modyford had been appointed the Governor of Jamaica in February 1664 with instructions to limit the activities of the privateers; he made a proclamation against their activities on 11 June 1664, but economic practicalities led to him reversing the policy by the end of the month. About 1,500 privateers used Jamaica as a base for their activity and brought significant revenue to the island. As the planting community of 5,000 was still new and developing, the revenue from the privateers was needed to avoid economic collapse. A privateer was granted a letter of marque which gave him a licence to attack and seize vessels, normally of a specific country, or with conditions attached. A portion of all spoils obtained by the privateers was given to the sovereign or the issuing ambassador.