[Dove]

Outside a few tiny movements, the Anabaptists were the first to object to infant baptism. Infant baptism was universal in the Catholic church, from the fifth century through the sixteenth, and even the Protestant Reformers adopted the practice. The Anabaptists were the Reformation's Reformers, and were named (by both Catholics and Protestants) after their most distinct and objectionable practice, that of insisting on adult baptism. (In fact, "Anabaptist" means re-baptizer -- they were named that in criticism by those who saw universal infant baptism as valid. This alone tells you something of the world they lived in -- a world that saw adult baptism mainly as "re" because infant baptism for everyone could safely be assumed.)

A lot of distinctive Anabaptist beliefs have gotten mainstreamed over the centuries, and what they were once best known for is now much more widely practiced. But the name sticks for historical reasons and the group still exists. You can read a summary of beliefs here: https://en.wikipedia.org/wiki/Schleitheim_Confession In the modern mileu, I would say what is most unusual and distinctive about them is pacifism.