For all the adaptations and mutations, the alphabet's order of letters has been relatively stable. In the 1920s, archaeologists found a dozen stone tablets used in a school in Ugarit, a city in what is now Syria, that are from the fourteenth century BC and preserve two orders of the Ugaritic alphabet. One, the "Northern Semitic order" is related to the Phoenician and Hebrew alphabets and features bits and pieces of an order familiar to Modern English speakers: a, b…g, h…l, m…q,r.

As the alphabet traveled around the world, those who adopted it did very little to change the basic order. Looking at this animation from the University of Maryland, you can see how things have remained largely the same between the Phoenicians and Latin. Long strings of letters, like abcdef, remain untouched for thousands of years.

So the order has ancient roots, but where does it come from?

I hate to disappoint you, but we're really not sure. The practice of having the letters in an established order makes sense: It’s easier to teach and to learn. Why some ancient people put them in that specific order, though, is unknown. Whoever did it didn’t leave any record that we know of explaining why they lined the letters up like that.

But this isn’t to say we’re at a total loss. Scholars have plenty of hypotheses about the order, relating to everything from astrology, musical scales, numbers, and poetry. Here are some of the ideas that have floated around among alphabet academics:

The first alphabet developed in Egypt might have been adapted from some part of the enormous system of Egyptian hieroglyphics, so it could be that the Egyptian system informed the order, too. * The ancient order was a long mnemonic device. Early users strung the letters together to correspond to the words of a mnemonic sentence or storyline. * In Semitic Writing: From Pictograph to Alphabet GR Driver touches on several explanations he’s come across, from “astral or lunar theories” to the order “representing a didactic poem” or being “based on the notation of the Sumerian musical scales.” * David Diringer, in The Alphabet: A Key to the History of Mankind, suggests that there’s no reason at all: “…it is highly probable that the matter has no particular significance...There is some appearance of phonetic grouping in the order of the letters of the North Semitic alphabet, but this may be accidental.” * The alphabet may have had a numerical component, and the order is reverse-engineered to the follow and match the numbers that the letters represented for merchants. Later civilizations hung on to the obsolete order for convenience’s sake.

While that’s pretty much the best we can do with the core of the order, we do have a better handle on the way a few specific letters fell into their places. New additions to an adopted alphabet always seem to get added to the end of the line, leading to x, y and z bringing up the rear.

When the Greeks borrowed the Phoenician letters, they added their own homemade letters to the end, like the ancestral X. When Alexander the Great’s empire came in contact with Rome later on, the Romans borrowed a few Greek words and adapted their alphabet again in order to write them. They borrowed Y and Z, which they’d kicked to the curb the first time around, and tacked them onto the end of the alphabet.