When did consonantal v start being transcribed as β?

1. When did Greek b become V?
2. Why are b and V interchangeable?
3. When did Latin V change?
4. How did ancient Romans pronounce V?

When did Greek b become V?

In Classical Greek, the letter beta ⟨β⟩ denoted [b]. As a result of betacism, it has come to denote [v] in Modern Greek, a process which probably began during the Koine Greek period, approximately in the 1st century CE, along with the spirantization of the sounds represented by the letters δ and γ.

Why are b and V interchangeable?

Although the Latin b and v were pronounced differently, they gradually merged in Spanish. As a result, some words are spelled differently but have the same pronunciation. Usually the context will make clear which word was meant.

When did Latin V change?

Greek transcriptions with β (beta) support dating the start of the change in the pronunciation of Latin V as early as 200BC.

How did ancient Romans pronounce V?

According to a consensus of Latin scholars, the letter V in ancient Latin was pronounced as [w]. This seems to make sense, because there was no distinguishing between V and U, so the letter V could mark either the vowel [u] or its semivocalic counterpart [w] (much like with the letter I).