Why do Latin letters have English pronunciations in Japanese?


The Latin letters A–Z are used in Japan today and they each have a name just
like in English. Take the first five Latin letters, A–E. Source:
<https://jisho.org>

> A 【エイ】【エー】
>
> B 【ベー】【ビー】
>
> C 【シー】
>
> Ｄ【ディ】【ディー】
>
> E 【イー】

It is pretty clear that all except one variant of B (ベー) are from English. I
don't actually know if that variant pronunciation is even used.

Surely in my mind the influence of Portuguese and later Dutch merchants and
Dutch studies (Rangaku) would mean there was already a need to have Japanese
names for those Latin letters, so it is only natural to assume the
pronunciation/names of those letter would be based on what the Dutch
themselves call them. E.g.,

> A 【アー】
>
> B 【ベー】
>
> C 【セー】
>
> Ｄ【デー】
>
> E 【エー】

And so on…

What is the history here? How come the English names for the Latin letters are
so prevalent in modern day Japan?

