Ladislaus admitted in his letter to Oderizius that he could not "promote the cause of earthly dignities without committing grave sins". Historian Bálint Hóman says that Ladislaus was referring to a developing conflict with Pope Urban II, who objected to Ladislaus's refusal to acknowledge the Holy See's suzerainty over Croatia. In the letter, Ladislaus styled himself as "king of the Hungarians and of Messia". Historian Ferenc Makk writes that the latter title referred to Moesia, implying that Ladislaus had taken the regions between the Great Morava and Drina rivers from the Byzantine Empire. No other documents refer to Ladislaus's occupation of Moesia, suggesting that if Ladislaus did occupy the region, he lost it quickly. Alexandru Madgearu says that "Messia" should rather be associated with Bosnia, which was occupied during Ladislaus's campaign against Croatia.