They are All Churches, in ASIA MINOR (TURKEY), some of them were started by PAUL himself. They were made of by Gentiles and Jews.
Revelation 1:11 (GW)
11 saying, “Write on a scroll what you see, and send it to the seven churches: Ephesus, Smyrna, Pergamum, Thyatira, Sardis, Philadelphia, and Laodicea.”
They were Seven REAL Churches in the First Century, and now in modern day western Turkey, the are still there as ruins. One of our seniors in our BIBLE STUDY GROUP, just got back from touring the ruins of those seven Churches, just before this Caronavirus got started here in the US. THEY REALLY EXISTED AT THE TIME JOHN WROTE REVELATION.