Saint Gerasimus was a native of Lycia (Asia Minor). From his early years he was distinguished for his piety. Having received monastic tonsure, he withdrew into the desert of the Thebaid (in Egypt). Thereafter, in about the year 450, the monk arrived in Palestine and settled at the Jordan, where he founded a monastery.
For a certain while St Gerasimus was tempted by the heresy of Eutyches and Dioscorus, which acknowledged only the divine nature in Jesus Christ, but not His human nature (i.e. the Monophysite heresy). St Euthymius the Great (January 20) helped him to return to the true Faith.