BASEL, Switzerland, Aug. 27 (JTA) — Jewish unity was the theme 100 years ago when Jewish delegates convened here to adopt a unified call for a Jewish homeland in Palestine. Unity was again a theme this week at ceremonies marking the centennial of the First Zionist Congress. Avraham Burg, chairman of the Jewish Agency for Israel and the World Zionist Organization, told the approximately 1,700 delegates attending the ceremonies that Jewish unity was still crucial even though the dream of Theodor Herzl and his colleagues had been realized with the creation of the state of Israel. Burg called for a “reform” in religious attitudes that “would enable Jews to live among Jews as equals despite the differences between each other.” His comments came at a time of increasing tension between Orthodox and liberal Jews over pending conversion legislation in Israel that liberal Jews believe will delegitimize their beliefs. Basel is serving as host for numerous events — including panel discussions, plays and exhibits — tied to the centennial celebrations, which will culminate with a formal ceremony Sunday night on the date and in the hall where Herzl concluded the first congress.