The personal pronoun I with capital letter

Why is the personal pronoum “I” always written with capital letter?
I have some grammar books, but I couldn’d find anything about it.
By the way, I’m Brazilian.

Hi Jorge and welcome to the forum.

As I understand it, the reason capitalizing the word “I” began was to make sure that “I” was clearly recognizable as a separate word rather than part of the word before or after it. It began hundreds of years ago — when people had no PCs, word processors, typewriters, etc. and were forced to write things by hand. :shock: :lol:

Here is a link: