The Rikken Seiyūkai (立憲政友会 Constitutional Association of Political Friendship) was one of the main political parties in the pre-war Empire of Japan. It was also known simply as the "Seiyūkai". Founded on September 15, 1900, by Itō Hirobumi, the Seiyūkai was a pro-government alliance of bureaucrats and former members of the Kenseitō. The Seiyūkai was the most powerful political party in the Lower House of the Diet of Japan from 1900 to 1921, and it promoted big government and large-scale public spending. Though labeled "liberal" by its own members, it was generally conservative by modern definitions. It often opposed social reforms and it supported bureaucratic control and militarism for the purpose of winning votes. It viewed the Rikken Minseitō as its main rival.