Decius came to Ephesus between 249 and 251 AD to enforce his laws against Christians. They were very hard and meant persecution. Seven noble young men, named Maximillian, Jamblichos, Martin, John, Dionysios, Exakostodianos, and Antoninos, were found to be Christians. The emperor gave them a short time for consideration, until he returned to Ephesus. So they gave their property to the poor, took only a few coins with them and went into a cave on Mount Anchilos to pray and prepare for death. When they heard of his return they said their last prayer in the cave and then fell asleep. When found asleep in the cave Decius ordered to bury them alive by sealing the cave with huge stones. A Christian came and wrote on the outside the names of the martyrs and their story.
Years passed, the Roman Empire became Christian, and Theodosius reigned. There are two Theodosius, so it may have happened between 150 and 200 years later. A rich landowner named Adolios had the Sleepers' cave opened, to use it as a cattle-stall. The sleepers awoke, thinking they had slept only one night, and sent Diomedes to the city to buy food, that they may eat before they give themselves up. Diomedes came into Ephesus and was amazed to see crosses over churches. People could not understand where he got money coined by Decius. Finally they learned that the last thing he knew was Decius's reign. The bishop and the prefect went up to the cave with him, where they found the six others and the inscription. Theodosius was informed, he came and the sleepers told him their story.
At this time some heretics denied the resurrection of the body, but every one rejoices at this proof of resurrection. The sleepers, having improved the occasion by a long discourse, then died praising God. The emperor wanted to build golden tombs for them, but they appear to him in a dream and ask to be buried in the earth of their cave. The cave is adorned with precious stones and a great church built over it. Every year the feast of the Seven Sleepers is held.
Symeon Metaphrastes (q.v.) in his "Lives of the Saints" for the month of July.