One of Mohyla's greatest impacts is in higher education in the lands of today's Ukraine through the school that would later become the Kyiv-Mohyla Academy.
Prior to this school, aristocratic youth would need to attend one of the Polish Jesuit academies, or travel west, where they would often need to convert to Roman Catholicism in order to be allowed to matriculate. Mohyla, who in 1628 had become archimandrite of the Kyiv Monastery of the Caves, received the blessing of the Patriarch of Constantinople in 1631 to found a monastery school.
In a radical move, the school, while Orthodox, would be oriented towards Latin and Polish, not Greek and Slavonic. This put it in the cross-hairs of both the Cossacks and the Jesuits. The latter were furious at this challenge to their educational monopoly — doubly insulting since it came from what they would have considered to be a bunch of unsophisticated Ruthenians. The Cossacks, though, deeply distrusted the teaching of Latin and Polish, and suspected the teachers of Uniate tendencies. While Mohyla was powerless with respect to the Jesuits, he used skillful maneuvering to defuse the potentially explosive situation with respect to his Orthodox coreligionists. He did this by proposing a merger between his Caves school and the school of the Kyiv Epiphany Brotherhood, which had been in existence since 1615. This merger, which formed the Collegium Kijoviense, was successfully finalized in 1632 with the full support of the Cossacks.
The Collegium's emphasis on Latin and Polish was fundamental to its success. As Mohyla argued in his 1644 work Lithos or Stone, although Greek and Slavonic were needed for religious reasons, as citizens of the Polish Crown, Ruthenians needed to know the languages of sophisticated society, namely Polish and Latin. After all, it would not be right for an aristocrat to address a fellow Senate or Diet member in Greek or Slavonic, or to have to always bring along an interpreter.
Mohyla's Collegium allowed local elites to get a good education close to home and in an Orthodox milieu, thereby preventing their complete Polonization. Amazingly, this Latin and Polish emphasis persisted well into the 18th century after the school had been placed under control of Moscow, and so to some degree it also delayed the effects of Russification.
Perhaps even more importantly, the Collegium raised the level of intellectual life in Kyiv, and helped to dispel any cultural inferiority that the local elite may have felt with respect to the broader Polish society.