The desire to return to Zion, another name for the City of Jerusalem, already appears in the Hebrew Bible. The rise of the European national ideology in the second half of the nineteenth century paved the way for the perception of the Jewish people as a national entity with a right to a state of their own. In addition to fulfilling a Biblical promise, a Jewish state with Jerusalem as its capital would provide a place for Jews to live free of persecution.
At the First Zionist Congress in Basle in 1897, under the aegis of Theodor Herzl, Zionism was promoted to a political ideology. The Zionist Congress manifested itself as the representative (parliament) of the Jewish people and as such lobbied among senior political officials. In the meantime, small groups of Jewish immigrants settled in contemporary Palestine.
See for additional information the theme article Zionism and hakhsharah.