Why is the Council of Jerusalem not considered as the First Ecumenical Council of the Catholic Church?

According to the [Catholic Encyclopedia](https://www.newadvent.org/cathen/04423f.htm) , a question about the First Ecumenical Council: Nicaea I (325) I have read that the Council of Jerusalem is labeled as a "General Council." Furthermore, it is my understanding that the terms "General Council" and "Ecumenical Council" are synonymous. If that is correct, then why is the Council of Jerusalem (50 A.D. or thereabouts) not considered to be the First Ecumenical Council of the Catholic Church?