The article deals with the historical imagination in the burgher's milieu in the late Renaissance Polish kingdom. The main aim of the article is the investigation of the changes that occurred in the perception of the remote past. The article focuses on the mechanisms of a usable past construction. In 1578, in order to obtain equal economic rights with the dominant Catholic burghers – mostly of German origin – in Lemberg, local Armenians stated that their ancestors were invited by the Galician prince Daniel and were then settled by his son Lev/Leon (1264-1301) in Lviv at the time of the city's foundation. In 1597, in their complaint, Catholics allowed that the statement of the invitation of the Armenian ancestors was a real fact but accused "Armenian warriors" for participating in the hostile incursions led by Prince Daniel or Lev together with the Tatars in the 1250s-1280s against Poland. In this way, the magistrate won the trial in 1600. I argue that for their pseudo-historical argument Catholic patricians creatively reinterpreted some passages from Marcin Cromer's book "On the origins and deeds of the Poles" (1555, 1558, 1562, 1568, 1589). Then, Armenians changed their tactics and stated in 1631 that their noble ancestors took an active part in the wars between Poland and Teutonic Order in late fourteenth – early fifteenth centuries. Thus Armenians converted their ancestors into good patriots of Poland when the Germans were the main enemies. During the trials townspeople perceived changes in their past. It also reflects a level of historical reading in Polish history and the emergence of the Battle of Grunwald battle as part of a Polish national myth. Thus Renaissance book-printing and book-collecting directly influenced the burgher's historical imagination and their judicial argument. City elites "privatized" a book, which had been sacral property of Church, and made it their tool to use for their practical needs. They also privatized and instrumentalized the based-on-books past. The arguments used by both sides during their conflict correlated with the urban elites' aspirations to acquire noble status. It also reflects the process of transmission of high culture models – Sarmatian Renaissance – to the lower estates of the Kingdom.