God
Abraham
Moses
David
According to Genesis 29:35, Leah gave birth to Judah at about 1750 BCE. His father Jacob was the son of Isaac, the son of Abraham. This was the beginning of all twelve Israeli tribes, Judah being one of them.
Genesis chapter 49 tells of a gathering of the twelve to their dying father Jacob, also called Israel (meaning: God's rule), to hear his pronouncements of their futures. Jacob tells Judah that his tribe will be the greatest, and will be lawgivers.
As to important leaders, if Judah, Jacob, Isaac and Abraham are historically too early for your purposes, Numbers chapter 1 has Moses calling upon the heads of house of every tribe to bring forth men, twenty years of age and upward as able to prepare for war. Representing Judah is Nahshon the son of Amminadab. Then in Numbers chapter 13 tribal heads or rulers were sent to scout the land of Canaan. Representing Judah is Caleb the son of Jephunneh. Numbers chapter 34 has Caleb representing Judah in dividing up the land of Canaan, now Israel, for the tribes. Joshua chapter 15 describes the land Caleb got for Judah. I Chronicles chapter 2 has too much tribal family information to digest here, but interestingly it tells of Judah's firstborn son being killed by God because he was evil.
GOD is their important leader.
The leaders of Judaism are Rabbis. The followers of Judaism are the Jewish people.
There are no churches in Judaism.
rabbis
rabbis
Moses.
Rabbis.
Judaism is not a centralised religion and does not have a single leadership. The members of Judaism are called Jews.
It was Judaism.
Rabbis.
There is no one biggest person in Judaism. There have been thousands of leaders, teachers, and rabbis.
Judaism isn't a centralised religion so leaders are at the community level. Leaders can be religious or secular depending on how they're associated with their community.
Each community has its own Rabbi, of which there are thousands.