Was Israel founded with 13 tribes?

Answer 1

No. There were twelve tribes; but these twelve were counted two different ways depending on the purpose. The tribes were: Reuben, Simeon, Levi, Judah, Issachar, Zebulun, Gad, Naphtali, Dan, Asher, Joseph, and Benjamin.

For certain purposes, Joseph and Levi are not counted, and the two halves of Joseph (Menashe and Ephraim) are counted.

Answer 2

No. There were twelve tribes. In addition to what my colleague Dan Galilee notes below, I would like to add that Leah's seventh child, Dinah, was not considered a tribal forefather, so she is not counted even though Jacob had thirteen children when she is counted.