 Complete the following phrase:  Yakov Hanecki was born in Warsaw, Vistula Land, Russian Empire, the son of Stanislav von Fürstenberg, a beer manufacturer of German descent, who had adopted Poland as his homeland. In 1896 he joined the Social Democracy of the Kingdom of Poland SDKP - later the Social Democracy of the Kingdom of Poland and Lithuania SDKPiL led by Rosa Luxemburg and her lover, Leo Jogiches. He moved to Germany in 1901 and studied in rapid succession at Berlin, Heidelberg, and Zurich universities. From 1902, he was a professional revolutionary, normally based in Cracow, under Austrian rule, organising the transport of illegal literature across the Russian border. In August 1903, as a member of the Main Administration of the SDKPiL, he was one of two Polish delegates to the 