That's why some crosses have "INRI" written: Iesus Nazarenus, Rex Iudaeorum

Hence Iesus Nazarenus in Latin.

It was likely caused by the transition from right-to-left to left-to-right writing

So basically, while Egyptian hieroglyphs didn't have a specific writing direction, boustrophedon was a very common system, where you'd start writing in one direction, and then switch direction on the next line (so the first letter of the second line is right under the last letter of the first line).

The Phonecian script, however, started to stick to right-to-left for writing. When the greeks first adapted the Phonecian alphabet for the Greek language, they wrote in right-to-left and boustrophedon. When writing boustrophedon, they would flip the letters to match the writing direction. When left to right started to gain popularity, the flipped letters were used, and left-to-right is now what is used in the Greek alphabet and its descendants.

Sometimes, you just gotta go for style points.

Maybe because at that point the Roman Empire controlled most of that part of the world? Also maybe literacy was increasing, requiring more consistency? Then as the Roman Empire declined centuries later different cultures only iterated in their own language? Just some guesses.

My guess would be it's easier to write quickly like that when you write left to right.

Easier to read in your rear view

Pronunciation evolution differentiated U and V more and people started differentiating that with an extra sign. As in, the Roman V was pronounced kinda like both and not like today's V - the Roman symbol V is not the modern letter V. You may notice that modern media about ancient Rome have been making Vs sound more like Us.

It looks like V became U, V, & W