What is the origin of the phrase lost his marbles come from?

Answer 1

The term derives from the boy's game of marbles which was hugely popular in the US during the last 1/3 of the 19th through the first 1/2 of the 20th centuries.

Marbles were almost always wagered through playing a game of "keepsies" whereby each of the players placed an agreed upon number of their marbles equal to those placed by the other players into a circle drawn in the dirt and by knocking other player's marbles outside of the ring by shooting at them using a "shooter" marble from outside the ring, the shooter kept the marbles he "scored" and continued shooting until he missed then it was the next players turn. When all marbles were gone from inside the circle, the game was over and the players kept whatever number of marbles they "scored". It wasn't necessary to keep score in a casual game such as this since whatever marbles each player had afterwards was the score. Since all marbles entered were at risk, it was possible for one or more players to lose all their marbles by the game's conclusion.

Since marbles were the prize possessions of many little boys, it is safe to assume that one who had lost all of his might wander around the streets in a daze, perhaps the shock of having been wiped out casting a pall of funk or insanity over the loser, especially if viewed by passersby and out of context. Having lost all ones marbles may have caused the loser to express great anger - an early, alternate connotation of the saying which eventually gave way to the term meaning that one who lost his marbles has gone insane, which is logical as being angry or "mad" can easily morph to "madness" or insanity.