Baring-Gould’s sources: Greek Menæa. Authority, Theodoret, in his Philotheus, c. 6.

Simeon the Old dwelt a life of solitude in a cave, feeding on vegetables. One day some travellers arrived at his cell, having lost their way and asked the old hermit to direct them to a certain fort for which they were bound. The hermit called two lions from the desert, and gave them to the travellers as guides. This incident was related to Theodoret by one who was present on the occasion. When a large number of disciples assembled under his direction, the aged Simeon went away to mount Amanus, near Antioch, and there built a monastery. But afterwards, being desirous of ending his days on Sinai, he went into the desert of that mountain. And there he saw one day two hands raised from the mouth of a cave. Thinking it might be a snare of the devil, he approached with caution. At the sound of his footsteps the supplicating hands were drawn in, and he saw no man; then he cried to the dweller of the cave to come forth, and there issued out of it an old hermit dressed in palm leaves, who said that he and a brother hermit had come to establish themselves on Sinai, and they had promised each other never to separate. Now before they reached the holy mount the brother hermit died; so the survivor buried his corpse, and, faithful to his promise, tarried by his grave till the Lord should call him; and every day a lion brought him a bunch of dates. Now when Simeon had partaken of his dates, and they had sung together the matin office, he went on, and reaching Sinai with his monks, established on the mountain two monasteries, one at the summit, and the other at the foot.