The best explanation seems to stem from Southerners' penchant for keeping a name going down the line, especially for males. You end up with John Smith Jr., III, and IV in one family, and calling a child by his middle name is an easy way to distinguish between him and his father.

Is it weird to go by your middle name?

The good news is, having a middle name as a first name is actually quite common! There aren't official statistics, probably because middlenameites are too classy to make a big deal out of it, but we feel a kinship with each other.

Why did people go by their middle names?

But the way we use middle names today originated in the Middle Ages when Europeans couldn't decide between giving their child a family name or the name of a saint. They eventually settled on naming their children with the given name first, baptismal name second, and surname third.