Many Bible scholars teach that the Seven Churches of the Apocalypse represent seven distinct ages of church history:

EPHESUS - the Apostalic Church
[Pentecost A.D. 100]
SMYRNA - the Persecuted Church
[A.D. 100-316]
PERGAMOS - the World Church
[A.D. 316-800]
THYATIRA - Medieval Church
[ A.D. 800-1517]
SARDIS - Rise of the State Church
[A.D. 1517-1750]
PHILADELPHIA - Missionary Church
[A.D. 1750-1900]
LAODICIA - Apostate Church
[A.D. 1900 - present]