The six-year exploration licence Gilbert had secured by letters patent from the crown in 1578 was on the point of expiring, when he succeeded in 1583 in raising significant sums from English Catholic investors. The investors were constrained by penal laws in their own country, and loath to go into exile in hostile parts of Europe; the prospect of American settlement appealed to them, especially as Gilbert was proposing to seize some nine million acres (36,000 km2) around the river Norumbega, to be parcelled out under his authority (although to be held ultimately by the Crown).