The labour unions were prepared to unite and work together with the SDAP. The Dutch Federation of Trade Unions (Nederlandsch Verbond van Vakvereenigingen, NVV) was founded in 1905 by Henri Polak. After the railway strike the conflict between revisionists and orthodox Marxists intensified both within the SDAP and internationally. In 1903 Troelstra lost control of Het Volk to the orthodox faction. In 1904, the orthodox faction had another victory, when revisionism was forbidden by the conference of the International in Amsterdam. On the eve of the 1905 election the revisionists won a crucial victory. The party decided to support liberal candidates who were in favour of universal suffrage. The party gained one seat, meaning it held seven seats and supported the liberal minority government, led by De Meester. Many members of the SDAP were irritated by the behaviour of the orthodox Marxists who were continuously denouncing moderates. Troelstra openly attacked the orthodox Marxists and the party congress in a formal resolution declared to oppose all labelling opportunists and revisionists. The orthodox Marxist chairman Tak resigned and Vliegen became chairman. Tak also lost control of Het Volk to Vliegen. In 1907, a group of orthodox Marxists around David Wijnkoop founded the magazine De Tribune, which attacked the revisionist leadership of the SDAP. Troelstra and other leaders removed David Wijnkoop and his associates from the party ranks in 1909. Wijnkoop founded the orthodox Marxist Social Democratic Party (SDP) the same year. The SDP later became the Communist Party of Holland. This was one of the first splits within the European labour movement. In the 1909 election the SDAP held on to its seven seats, but their liberal allies lost many seats to the confessional parties, who won a majority of sixty seats. In the knowledge that they could not accomplish anything in parliament, the SDAP focused on the extra-parliamentary movement for universal suffrage, for both men and women, regardless of class. The party's original strategy was to organise mass strikes for universal suffrage. But the socialist union NVV feared reprisals from employers. So the SDAP decided to start a petition. In a mass demonstration in The Hague on Prinsjesdag the petition was presented to parliament. The SDAP called it Roode Dinsdag (Red Tuesday). The demonstration led to considerable controversy, when Queen Wilhelmina decided not to attend the Prinsjesdag ceremonies. For the 1912 Prinsjesdag the Red Tuesday was forbidden. During this time the