Initially, the Romans thought the Greek versions of 'y' and 'z' were unnecessary. They were adopted into the Latin alphabet around the 1st century BC. This was primarily to spell foreign loanwords.
Old English
Old English followed this pattern, with variations. The letters ‘j‘ and ‘v‘ did not exist in Old English, and ‘k‘, ‘q‘ ‘z‘ were extremely rare.
'Y' had a dot above and was initially a rounded vowel pronounced (/y/ or /yː/) similar to the German ü or French u. This was distinct from 'i' or 'u'. like a modern 'i'. An example comes in the Old English word fȳr (fire)
Greek letter names
English does not follow the Romance language convention of naming Y after its Greek origin: i griega (Spanish) i grec (French and Romanian), and i greca (Italian)