(CNN) -- Poland's former deputy prime minister Andrzej Lepper was found dead in his apartment in the capital, Warsaw, on Thursday, his party said in a statement.
Lepper, 57, who headed Poland's populist Self-Defense Party, served as deputy prime minister from 2006 to 2007, as part of a coalition government led by the Law and Justice Party. He also served as agriculture minister.
His party paid tribute to a "distinguished politician, statesman" who had founded and led the party and Trade Union of Farmers' Self Defense.
He first rose to national prominence in the 1990s, when he helped organize mass protests by farmers over a lack of state help for those affected by a disastrous drought, his party's website says, forming the trade union and then the party.
The party statement said he had left its members "suddenly, leaving a better world of truth and love, as a true Catholic who believed sincerely and warmly."
His legacy was a vision of a more just world, the party said.
Lepper's "third way" politics called for a different approach to capitalism, through "a social-economic system that would effectively combine freedom of enterprise with social responsibilities of the state," according to the party's website.
CNN's Bharati Naik contributed to this report.