By 1608–1609 he was imprisoned in Fleet Prison in London. Documents as to the actual cause of his incarceration are lacking, but Persons, citing Boyan, appears to believe it was because he was unable to repay the large sums of money borrowed to repurchase the family estate. That, combined with his recusancy, were sufficient reasons for incarceration. In 1614, the people from whom he had borrowed money petitioned the House of Lords to sell the Tregian lands to repay their loans.