"ե + ւ" was written as "և" ever since lower case Armenian letters were invented in 10th century.
Here are pictures of a few ancient handwritten Armenian manuscripts:
every single one of them uses «և» ligature.
Here are a few pages from the first printed Armenian book:
and again they all use «և» ligature (among many others).
In fact in Grabar if «ե + ւ» is written as «ե ւ» it is pronounced as "yo" or "yu" for example «ե ւթ» is pronounced as "yot" (number 7) or «հարե ւր» (haryur -> "hundred"). However, whenever it was supposed to be pronounced as "ev" it was always written as one symbol և․ This is a basic rule of Classical (Grabar) Armenian, Middle Armenian, and also the modern Eastern and Western Armenian.
«ե ւ» type of writing is a fairly recent invention. I assume it was caused by the fact that old PC software was not able to deal with ligatures very well.
Սահակ 01:31, 21 July 2008 (PDT)
Regarding the "yev" ligatures, I know about the rule and its historicity, but it is not common in the books written in the diaspora. I am almost 62 years old and have seen Armenian writing and read it since I was 5 years old, that is, for almost 60 years now, in books, magazines, newspapers, etc., and the "yev" ligature appears very rarely in Western Armenian, unless the books have been printed in Armenia. So, to us Westerners, the "yev" ligature feels very normal when reading Eastern Armenian or Grabar, but it comes across as an annoying quirk when reading Western Armenian; and I am not alone in feeling this way. That is why I had written that comment there. However, as I said earlier in my previous message, I think it is better not to include it, because it will confuse people, since not everyone cares and not everyone will understand what we are talking about.
Nice talking to you. I don't have a lot of people with whom to talk about these things, so I welcome every comment, information, and chit-chat in general about things related to Armenian language and letters. The problem is that I don't have much knowledge about the matter, and I am not a writer, a scholar or a computer programmer, so you need to be patient with me if you want to keep communicating with me.