The Ca' di Dio (or Domus Dei) was one of eighteen hospitals built in Padova during the Middle Ages. Its foundation, due to the action of the lay confraternity of Santa Maria dei Battuti, took place between 1263 and 1265, in an area located approximately halfway between the churches of Santa Caterina and San Biagio, corresponding to today's number 46 of Via Santa Sofia. The building consisted of the rooms of the actual hospital (divided into a men's and a women's ward), a church and a large vegetable garden that extended towards the interior of the built area. Compared to the other Padovan hospitals, located near the city gates, the Ca' di Dio was located within the city circuit, in a position that was to guarantee it a predominant function in the urban hospital network, as also attested by the fact that the institute was the first to be mentioned in the municipal statutes of 1275.
Like the other medieval hospitals, in the beginning the Ca' di Dio offered assistance to different categories of the population: the poor, the sick, pilgrims, widows and orphans; only during the fifteenth century (between 1430 and 1460) did the institution specialize in the care of abandoned children, an orientation that distinguished it for the following centuries.
The seat of the institute remained in Via Santa Sofia until 1784, when it was first moved near the monastery of San Giovanni da Verdara and, in 1847, under the new name of Istituto degli Esposti, in Via Ognissanti: here, the “wheel of abandoned children", can still be seen today, where parents could deposit babies without being seen.
The children were usually accompanied by small sheets of paper indicating their name or whether they had been baptised; they often also carried objects or other distinctive signs, such as paper images cut in half, which would have allowed their parents to identify them later. In the State Archives of Padova there are still many of these "signs", some of which are reproduced here.