The Sacra Culla, or Holy Crib, is reserved for veneration in a silver reliquary by Giuseppe ...
Many scholars, however, place the origin of the presepio tradition in the thirteenth century. In 1223 Saint Francis of Assisi commissioned Giovanni Vellita from the town of Greccio to build a large-scale manger scene for the faithful to venerate on the anniversary of the Christ’s birth. Vellita therefore constructed a three-dimensional nativity scene out of straw in a cave of Greccio and Saint Francis had Christmas Mass celebrated there that year. According to the various accounts, Francis also used real people and living animals to illustrate the revered event.
http://www.sacredarchitecture.org/articles/a_roman_christmas_ritual_micro_architecture_and_the_theatre_of_the_presepio/