Staszic was a keen observer of the proceedings of the Great Sejm, spending much time in Warsaw since the Sejm began its deliberations in 1788. He continued publishing new books and pamphlets. His "Warnings for Poland, coming from the current European politics and natural laws, by the writer of the remarks upon the life of Jan Zamoyski" ("Przestrogi dla Polski z teraźniejszych politycznych Europy związków i z praw natury wypadające przez pisarza uwag nad życiem Jana Zamoyskiego", 1790), together with his previous "Remarks", are considered among the most influential works of the Polish Enlightenment. In "Warnings", he criticised the magnates of Poland and Lithuania, monastic orders and serfdom, and supported the enfranchisement of the townsfolk. Although he was not a participant of the Sejm, he was an influential onlooker, and through his widely read and discussed writings of the time is recognized as one of the founding fathers of the Constitution of May 3, 1791.