I was walking along the Tiber with my Italian friend Paola recently and she suddenly grabbed my arm and pulled me across the road into a side-street.
“I want to show you something”, she said.
The “something” was an unusual structure on the side of the Antico Ospedale di Santo Spirito in Saxia on Borgo S. Spirito, between the Ponte Vittorio Emanuele II and the Ponte Principe Amadeo Savoia Aosta on the same side as Castel Sant’Angelo. This hospital, one of the most ancient in Europe, was built by Pope Innocent III. Construction started in 1198.
Paola explained that the structure is a “wheel” (actually more like a drum) behind a grille where people used to abandon unwanted babies.
Mothers used to ring the bell to alert whoever was inside the church, place the baby in the drum and then spin the drum through 180 degrees so that the opening was inside the church and the baby could be removed.
The practice was for mothers to cut a coin in half, leave half with the baby and keep the other half so that mother and child could be reunited at some later date.
The prioress then marked the babies with a double cross on their left foot and “exposed” them again in the wheel to potential adoptive parents.
When Martin Luther visited the church in 1511, he was apparently scandalised by the presence of so many unwanted babies and thought they were all offspring of the Pope.
I found an interesting and fuller discussion of such wheels on a site about Sicilian genealogy.