At first the settlement was self-governed under the jurisdiction of a voivode from Chuhuiv that is to the east. The first appointed voivode from Moscow was Voyin Selifontov in 1656 who started to build a local ostrog (fort). At that time the population of Kharkiv was just over 1000, half of whom were local cossacks, while Selifontov brought along a Moscow garrison of another 70 servicemen. The first Kharkiv voivode was replaced in two years after constantly complaining that locals refused to cooperate in building the fort. Kharkiv also became the centre of the local Sloboda cossack regiment as the area surrounding the Belgorod fortress was being heavily militarized. With the resettlement of the area by Ukrainians it came to be known as Sloboda Ukraine, most of which was included under the jurisdiction of the Razryad Prikaz (Military Appointment) headed by a district official from Belgorod. By 1657 the Kharkiv settlement had a fortress with underground passageways.