Daendels then decided to use Javanese unpaid forced laborers to perform most of the heavy work, which resulted in thousands of deaths due to the difficult health challenges of the forests and marshes as well as the labor conditions. Many of Daendels' opponents became historical sources of the harsh conditions during the road construction. Major William Thorn wrote that about 12,000 natives are said to have perished during the construction. Nicolaus Engelhard, who was a governor over most of Java and who had to give up his position to Daendels, stated that 500 workers had died in Megamendung area nearby Buitenzorg (the present-day Bogor), excluding the number of people who died as the result of illness. Furthermore, Engelhard criticized Daendels for the thousand casualties resulting from the road construction in the woods of Weleri in Pekalongan region.