The Mathematical Universe: An Alphabetical Journey Through the Great Proofs, Problems, and Personalities by William Dunham is a fantastic book given to me by my Calc II professor. What it does is literally in the name, it goes through every major mathematical field or person (as in, A is Arithmetic, G is Greek Geometry, D for Differential Calculus, etc.) and describes the history of that field or the fields created by said person, the notation created, the theorems they went through, and so forth.

It's not the end all source but it's a darn good introduction to the history of maths and specifically the history of the major fields and theorems and the notation that came with them.