The article analyses one of the many conflicts in the middle of the 19th century in Vilnius, namely, the conflict between councillor Arianist Lukasz Markowicz (d. after 1583) and the city authorities, i.e. municipal council and Vogt Augustinus Rotundus. The religious interpretation of the conflict predominates in the historiography, as under favourable circumstances Catholics pulled off the radical Protestant. Reading the earlier-known sources in a different way and handling new ones, the author reconstructs the process of the case which lasted more than 30 years, and gives a new interpretation of it. At the end of the research, the conclusion is drawn that the conflict had economical grounds, specifically because Lukasz Markowicz had lost some lawsuits: the biggest losses were a lost house and the monopoly of making vodka. The conflict became a political one (in the context of the city), because Lukasz Markowicz, which was unseated from the council, contested legitimacy of some actions of Augustinus Rotundus himself and the structure of the board. due to political (unseating from the council) and financial (a huge share of his property) losses, Lukasz Markowicz could temporarily become more radical in his religious standpoint, turning to Arianistic beliefs. Nevertheless, there is strong evidence that he was not of the leftist Arianistic views, but rather vice versa. This allows to consider the question of the conformity of words and actions and their evolution in the life of this Arianist
