Today someone born with such a condition in the United States or Western Europe can reasonably expect to receive humane treatment, an education tailored to their abilities, and medical care.
But let’s say that I’m born with Down Syndrome in the year 1300 (or 800, or 1841, whatever). How would people treat me? Would my family’s reputation suffer because of my birth? Would I be taught relevant life skills like digging a ditch or planting seeds, or would people just not bother?
I’m also interested in people’s general perception of them at the time. I work with adults who have these conditions, and I’ve noticed that in the United States in 2020, people we meet in the community are usually very understanding, patient, and respectful with them; it’s also considered politically incorrect to use slurs like “retard.” Was this the case centuries ago, or is it the product of a more liberal era?
/u/sunagainstgold and /u/itsallfolklore have previously addressed the related question How did people in the Middle Ages and earlier deal with Down Syndrome and autism?
Sunagainstgold has also written about this on another thread about how people with Down's were "explained" in times gone by.
/u/Deirdre_Rose has addressed the "ancient times" aspect of your question in this thread.
Note that there may be other threads on this topic I couldn't find because "Down Syndrome" is a more specific search term than "disabled" or "disability".
EDIT: Fixed typo for attribution
(Thanks for the h/t, /u/voyeur324!)
Just to add quickly--Irina Metzler, who is the #1 scholar of disability and PWD in the Middle Ages, has a pretty recent book about people with intellectual disabilities, if you're interested. Looks like the Kindle version is ~$33, which isn't bad for an academic book (I guess.)