He lived during the years when Constantinople was held in captivity by the Crusaders, and the Imperial government was in exile in Nicaea. Simon fled the world at a young age and traveled to the Holy Mountain, where he submitted himself to a strict but wise Elder for many years. In time, seeking greater seclusion, he moved to a small cave on the western side of Mt Athos, near a cliff that towered a thousand feet above the sea. One night, a few days before the Feast of the Nativity, he saw a star move across the sky and come to rest above the cliff near his cave. Taking this as a demonic delusion, he ignored it; but on the Eve of Nativity, the star once again took its place above the cliff, and Simon heard a voice from heaven saying 'Be in no doubt, Simon, faithful servant of my Son! See this sign, and do not leave this spot in search of greater solitude as you have in mind, for it is here that I want you to establish your monastery, for the salvation of many souls.' Soon afterward, three young monks from wealthy Macedonian families, who had heard of the Saint's holiness, came and laid their wealth at his feet, asking that he accept them as disciples. Simon sent for builders and ordered them to construct a monastery on the very edge of the precipitous cliff. The builders at first refused, saying the work was much too dangerous; but, persuaded by a miracle worked through the Saint's prayers, they were convinced. As soon as the building was finished, the monastic community began to grow rapidly.

In his own lifetime St Simon was the source of many miracles, prophecies and healings. Once the monastery was attacked by Saracen pirates. Simon went to meet them with gifts, hoping to dissuade them from attacking. When the pirates attacked him, they were blinded, and the arm of one of them was paralyzed when he attempted to strike the Saint. All of them were healed when the holy man prayed for them, and at this wonder they all repented, received Baptism and became monks.

Saint Simon reposed in peace. A fragrant, healing balm afterwards flowed from his tomb in great quantities, so that he came to be called Myroblytis, 'Myrrh-gusher' or 'Outpourer of Myrrh.' In subsequent years, the monastery was destroyed and rebuilt more than once, and no trace now remains of the tomb.