The "u" and "v" in older written English is confvsing

In older written English, there seems to be one written letter which
served the purpose of 2 functions: to transliterate both the "u" and
the "v". The symbolic representation was the "v". So, in the older
days, a word like "Massachusetts" would be "Massachvsetts".

I've got qvestions on this arrangement:
1. How would the word "vulgar" be spelt? As "vvlgar"?
2. When did the letter "u" come about?
3. I noticed that the "W" is pronounced "Double-u", when in fact,
it's a "double-v". Any comments?
4. How did people know how to pronounce words which ambiguated the
"u" and "v"?
.