IN 1399, AFTER the death of Spytek of Melsztyn, Władysław II Jagiełło faced, once again, the need to find a new governor for Podillya— or, rather, for its part he considered his own. The king chose his younger brother, Švitrigaila, who began calling himself a prince of Podillya after receiving its western part. At the end of 1401 Švitrigaila fled to the Teutonic Order, and western Podillya came under the administration of starostas (the representatives of a king).

Despite receiving the Grand Duchy of Lithuania to reign over for life (the well-known, in historiography, Pact of Vilnius and Radom, 1401), Vytautas never ceased making plans for reclaiming the whole region of Podillya. Until his death, in 1430, the confrontation between Vytautas and Władysław II Jagiełło propelled the history of the area. Competing for influence in Podillya, the two used different approaches. Władysław II Jagiełło relied on the incoming members of nobility aiming at the complete incorporation of Podillya into the Polish Crown, whereas Vytautas granted his estates as fiefs to both Ruthenian and incoming noblemen in order to dominate in Podillya. Some adjustments were made in 1410, when the king made Vytautas the life-long owner of Podillya in gratitude for his aid in the Battle of Grunwald.

The death of Vytautas on October 27, 1430, meant that Podillya was supposed to be under the control of Władysław II Jagiełło, who had outlived his opponent. The new ruler of the Grand Duchy of Lithuania, Švitrigaila, had his own view on this, since he had been the prince of Podillya for two years at the beginning of the century.

The region's fate, at least of its western part, was decided by the pro-Polish noblemen headed by the Buczacki brothers, with the support of the Bishop Paweł from Bojańczyce. Military activities in 1431/ 32, ended with a ceasefire signed in 1432, led to the partition of Podillya into western and eastern halves and the establishment of an internal border that divided the unitary historical region. In the second half of the 1430s Władysław II Jagiełło's attempts to take control over eastern Podillya failed.