There was no letter U in the alphabet. Well, that’s not the entire story. There was the sound for the letter we call U, but it didn’t look like U. It looked like V. The Classical Latin alphabet had only 23 letters, not the 26 that we have today. (This is why the W looks like a double V but is pronounced like a double U. Learn more about the history of W here.)
For a very long time, U and V were allographs. What’s an allograph? An allograph is a variation of a letter in another context. Uppercase and lowercase letters are allographs. Before the use of the letter U, the shape V stood for both the vowel U and the consonant V. In the picture below you can see the letter V used in places were it would be pronounced as a U.
The letters begin to look different in the Gothic alphabet in 1386; however the use of the u was not widespread. When scribes did use a u, it was in the middle of words, e.g. save was saue, but upon was vpon. It wasn’t until printing standardized letter shapes in the 1600s that the letter U became regularly used. First, in the 1500s, Italian printers started distinguishing between the vowel U and the consonant V. However, the V continued to be used for the U sound at the beginning of words. In 1629, the capital U became an accepted letter when Lazare Zetzner, a printer, started using it in his print shop.
The letter Z was almost removed from the alphabet. Read Z’s story here.
Covld you still read if we vsed v for u?