The Torah observant Jews including the apostles were gathered
b'SHEM Yah'shua
as required in Jerusalem for the celebration of the YHvH commanded
Feast of Shavuot ( also known as Pentecost in Koine Greek ) when
the Ru'ach HaKodesh descended on them.
All of the apostles were commanded to only go to the Jew.
Later Yah'shua chose Paul and Paul only to go to the gentiles.
The Roman church was founded after the Pagan Council at Nicea
Well put, imho.