The largest relics of the Holy Crib are preserved at the church of Saint Mary Major in Rome and were probably brought there from the Holy Land during the pontificate of Pope Theodore (640-649) and in the course of succeeding centuries the church came to be visited by the devout pilgrims from all parts of the Christian world. The remains of the crib preserved at St. Mary Major consist of five pieces of board which are found to be taken from a sycamore tree of which there are several varieties in the Holy Land. Two of the pieces, which like the other three, must have been originally much longer than they are at present, stood upright in the form of an X, upon which three other pieces rested, supported by a sixth piece, which, however, is missing, placed across the base of the upper angle of the X. We may conclude from this that these pieces of wood were properly speaking mere supports for the manger itself, which was probably made from the soft limestone of which the Nativity grotto was formed. Devotion to the crib is no doubt of very ancient origin, but it remained for St. Francis of Assisi to popularize it and to give to it the tangible form in which it is known at the present time. Devotion to the crib has since spread throughout the Christian world. Yearly, from the eve of Christmas until the day of the octave of Epiphany, a crib representing the birthplace of Christ is shown in all Catholic churches in order to remind the faithful of the mystery of the Incarnation and to recall according to tradition and the Gospel narrative the historical events connected with the birth of the Redeemer.