The Milk Grotto has been a center of Christian pilgrimage since ancient times. The current chapel was built in 1872 on the site of a Byzantine church from V century, of which the mosaic floor partly remains. According to thr tradition in this place the Holy Family have taken refuge during the Massacre of the Innocents and before their flight into Egypt.
See:
- Lorenzo Nigro, Bethlehem in the Bronze and Iron Ages, in the light of recent discoveries by the Palestinian MOTA-DACH, Vicino Oriente XIX (2015), pp. 1-24 - https://www.academia.edu/22280922
- Lucy O'Connor, “The Milk Grotto, Bethlehem,” Architecture and Asceticism, accessed October 14, 2020, http://architectureandasceticism.exeter.ac.uk/items/show/209.