Of all those exiled, the largest group of prisoners was sent to Chita, Zabaykalsky Krai, transferred three years later to Petrovsky Zavod, near Nerchinsk. This group, sentenced to hard labor, included principal leaders of the Decembrist movement as well as the members of the United Slavs. Siberian Governor-General Lavinsky argued that it was easiest to control a large, concentrated group of convicts, and Emperor Nicholas I pursued this policy in order to maximize surveillance and to limit revolutionaries’ contact with local populations. Concentration facilitated the guarding of prisoners, but it also allowed the Decembrists to continue to exist as a community. This was especially true at Chita. The move to Petrovsky Zavod, however, forced Decembrists to divide into smaller groups; the new location was compartmentalized with an oppressive sense of order. Convicts could no longer congregate casually. Although nothing could destroy the Decembrists’ conception of fraternity, Petrovsky Zavod forced them to live more private lives. Owing to a number of imperial sentence reductions, exiles started to complete their labor terms years ahead of schedule. The labor was of minimal travail; Stanislav Leparsky, commandant of Petrovsky Zavod, failed to enforce Decembrists’ original labor sentences, and criminal convicts carried out much of the work in place of the revolutionaries. Most Decembrists left Petrovsky Zavod between 1835 and 1837, settling in or near Irkutsk, Minusinsk, Kurgan, Tobol’sk, Turinsk, and Yalutorovsk. Those Decembrists who had already lived in or visited Siberia, such as Dimitri Zavalishin, prospered upon leaving Petrovsky Zavod's confines, but most found it physically arduous and more psychologically unnerving than prison life.