During his lieutenant-governorship, Raffles placed some restrictions on the local slave trade in line with wider British policy across its Asian territories, although slavery remained widespread and Raffles himself was served by a large retinue of slaves at his official residences in Java.[4] Under Raffles's aegis, a large number of ancient monuments in Java were systematically catalogued for the first time. The first detailed English-language account of Prambanan was prepared by Colin Mackenzie while Borobudur was surveyed and cleared of vegetation by H. C. Cornelius.[5] Raffles also attempted a replacement of the Dutch system of forced agricultural deliveries in kind with a cash-based land tenure system of land management, probably influenced by the earlier writings of Dirk van Hogendorp (1761–1822).