One of the aims of the pilgrims when they visited the holy sites was to take something of the blessing - eulogia in Greek- of the site back home with them, to serve as a remedy or source of protection. Such "souvenirs" often consisted of oil from the lamps that burned at the holy sites, water from the Jordan River, or earth from a place associated with a holy person. To transport these substances, a variety of containers were used, among them small flasks known as ampullae made of pottery, metal, or glass.
Israeli, Yael, and Mevorach, David, Cradle of Christianity, The Israel Museum, Jerusalem, 2000, English / Hebrew
Cradle of Christianity, Israel Museum, Jerusalem, 28/03/2000 - 30/01/2001