they split Arabs and Jews land, Palestine in half.
The development of the concept of the Southwest Levant as the Jewish Homeland was a result of the Conference of San Remo (1920) and the Mandate for Palestine (1922). In the latter document, the British Mandate of Palestine was specifically designed to be the "Jewish National Homeland". When Israel declared independence in 1948, Israeli leaders argued that the creation of the Jewish State was in continuance of this previously determined concept.
The Jewish leaders that interpret God's will are called Mashiach.
There is only one Jewish State, ISRAEL, and it was founded on May 14, 1948.
The Kohenim (priests), however, they weren't leaders of the Jewish people, they were in charge of the Temple.
A Jewish "leader" is a Rabbi which means teacher.
1948
Israel
The perform the wedding ceremony.
Rabbi
The Jewish leaders whom you're asking about are called Rabbis. Each Rabbi may lead a synagogue (Jewish place of prayer) and/or a Jewish community.
The Rabbis and sages. See also:Important Jewish leaders, prophets and rabbis
The Romans did not conquer anything in 1948.