Emperor Vespasian (reigned 69-79 CE) became a devotee of Sarapis after he participated in a miracle (a cure of a lame hand and a cure of a vision problem) in Alexandria (at 70 CE).
Domitian (reigned 81-96 CE) built a huge temple for Isis and adopted the Egyptian dietary laws after the priests of Isis saved his life.
Almost every city of the eastern Mediterranean had a temple dedicated to a god or goddess of a mystery religion.
These religions were so widespread that many Roman officials and emperors participated in them. In Alexandria Ptolemy IV Philopator (reigned 221-205 BCE) was a devotee of Dionysus.
The mysteries were cults into which a person was initiated (taken in).
The initiate was called "mystes," the introducing person "mystagogos" (leader of the mystes).
The cults of the mystery religions were influenced uniformly by the ideas of the Greek philosophers.
In the first century CE various mystery religions existed side-by-side throughout the Roman empire.
In Rome Emperor Augustus (reigned 44 BCE to 14 CE) was an initiate of the Eleusinian Mysteries and a devotee of Apollo.
Under his rule, in 28 BCE, a splendid temple of Apollo was built on the Palatine Hill.
The following features were common to all mystery religions.
Admission to the community was by a rite of initiation, a solemn consecration.