in the Po Valley by uniting different parts of agricultural working class. They were most successful in areas where the reformist union Federterra had been thwarted by employers. Syndicalists led large strikes by farm workers in Parma and Ferrara in 1907–1908, but these strikes failed as a result of employers' strikebreaking tactics and infighting among workers. In 1911–1913, syndicalists played an important role in a large strike wave in Italy's industrial centers. The syndicalist union confederation USI was formed in 1912 by veterans of both strike movements. British Wobblies were involved in two major strikes in Scotland, one at Argyll Motor Works and the second at a Singer's sewing machine factory in Clydebank. In 1906, several industrial unionists began to spread their ideas and organize workers at Singer's. In 1911, they organized a strike after a woman was fired for not working hard enough. The strike was cleverly defeated by management and most activists lost their jobs. The ISEL leader Tom Mann was also at the center of several labor disputes during the Great Labour Unrest, including the 1911 Liverpool general transport strike where he chaired the strike committee. In Ireland, Jim Larkin and the ITGWU led 20,000 during the 1913 Dublin lockout. After the ITGWU attempted to unionize Dublin's trams and tram workers went on strike, the city's employers threatened to fire any workers who did not sign a pledge to not support the ITGWU, thereby turning the dispute into a city-wide conflict in late September. Workers' resistance crumbled in January 1914. There was no international syndicalist organization prior to World War I. In 1907, CGT activists presented the Charter of Amiens and syndicalism to an international audience a higher form of anarchism at the International Anarchist Congress of Amsterdam in 1907. Discussions at the Congress led to the formation of the international syndicalist journal . The CGT was affiliated with the International Secretariat of National Trade Union Centers (ISNTUC), which brought together reformist socialist unions. Both the Dutch NAS and the British ISEL attempted to remedy the lack of a syndicalist counterpart to ISNTUC in 1913, simultaneously publishing calls for an international syndicalist congress in 1913. The CGT rejected the invitation. Its leaders feared that leaving ISNTUC, which it intended to revolutionize from within, would split the CGT and harm working-class unity. The IWW also did not participate, as it considered itself an international in its own right.