Well, for starters, the face we know as Bembo is from 1928. It was a modern revival of the faces which were cut for Aldus Manutius over 500 years ago. The name comes from the name of an author of a book that Aldus published. The face went into disuse after Aldus until it was revived as Bembo.

Off the top of my head, here are some good sources of information about Bembo:

A Tally of Types, by Stanley Morison
Printing Types: An Introduction, by Alexander Lawson
Twentieth Century Type Designers, by Sebastian Carter

great! do you actually have any ideas where i could find original examples of bembo? the version before 1928?

Just to be clear: Bembo didn't exist before 1928. The earlier types that it was based on didn't have a name as such, and I wouldn't call them earlier versions of Bembo. That would be like calling the New Testament an earlier version of the movie The Passion of the Christ.

Anyway, for samples of Aldus Manutius' printing, which might have examples of the typeface that inspired Bembo, try one of these:

The Art of the Printed Book, by Joseph Blumenthal
An Atlas of Typeforms, by Sutton and Bartram

Incidentally, the book that inspired the name was called De Aetna, by Bembo (the cardinal, not the font), published in Venice in 1495.