Pope St. Martin I suffered greatly in defence of the Faith. By his zeal and energy he incurred the hatred of the Monothelites, heretics who denied that Christ had any human will. So great was their influence that, after the plot to murder the Pope was frustrated by Divine Providence, the holy man was dragged to prison.
From there he was banished to the Crimea, where he died in 655. Although a Roman Pontiff, his feast is kept in the Greek Orthodox Church and in their Liturgy he is saluted as “The infallible and holy exponent of the divine dogmas.” His body was brought to Rome and buried in the Church of St. Sylvester.
(Source: The New Roman Missal, Rev. F. X. Lasance)