In the territory of Belgium,just like in any othercountry, it wasn’t unusal for a child to be abandoned at birth*. Surviving records are very interesting to study and even if they don’t give informations as to the child ancestors , they are a great source of informations to understand the context your foundling ancestor lived in.
Some registers are being kept in various archives repositories on a geographical basis, often in the State Archives of the province of the place where the child was discovered but also sometimes in the borough archives. In some 19th cities, there was a especially made box inserted in a door and who would give anonymity with the certitude that the child would be found. This box was called « le tour d’enfant » or « le tour d’abandon ». To give just a small example, more than 500 babies were left in this box for the sole year of 1841 in Brussels The foundling would have been taken in charge by the « meneur d’enfants » who often was the one to register the child in the said borough. This civil registration, to be found in the borough BMD’s just like any other record would always mentions the fact that the child is a foundling, the civil officer picking up his or her first and surnames at random, sometimes in link with the place the child was found in (« Léglise » could give a hint that the child was found in a church, « Laporte » that he or she was found on some doorstep) sometimes just being chosen in the Saints Calendar or in a book ( Greek and Roman Mythology were big favourites at a time) .
When the territory was under French governance (1795-1815) ,there were plenty of revolutionary themed names such as Marie Revolution or Liberté-Ignace Populaire !
Sometimes there would be a short description of the foundling clothes. A piece of paper or half of a playing card could also be found on the child , this was meant to give the parents, or rather the single mother as it often was the case , the possibility to take the child back later by providing the other half of the artefact. In some cases, those precious relics are being conserved in the records which adds a moving touch to it.
In the case of a first of last name mentioned on a piece of cloth or paper, this would be the name used for registration. It would sometimes also be mentioned that the child was already baptised even if he or she would be once again baptised. The mortality toll being what it was,you were never too sure !
Alas, not only was the infant mortality very high but hygiene low standards and over crowded orphanage often shared with the poor,the sick and the elderly surely didn’t help and also the parents weren’t sure that they would ever be able to come back to pick up their child should they wish to.
If the children didn’t died in infancy,they were sent to farms where they had to work hard. Later, they would enroll in the army or at a nearby mine or factory. In several cases that I worked on,and I had the case in my own family history, the foundling was to marry one child of his « foster » family , especially when there were several daughters and no heir to the farm. It was then a possibility for the foundling to start a new and better live.
It could be disappointing to find out a foundling in your family history but at the same time in case of a surviving record of your ancestor this information could give more informations on his or her life than you would have found otherwise. Of course you’ll be stuck on line of your tree but it also gives you a great subject to work on ( Were there any records kept ? Are there still available to see? Where did the children lived ? Is there any historical research made on the social history of the place your ancestor was found in ? Any statistics being made ? and many more questions that could come up at some point)
In case of a name or a baptism mentioned this could give more research hypotheses.
Always remember too that your foundling ancestor was a kind of survivor in his/her way !
* There are some recorded cases of older children being abandoned but they surely were a minority.