Any timeline of logic that fails to include Charles Sanders Peirce[1] is woefully incomplete. He discovered the existential and universal quantifiers and did seminal work on the relational calculus, to name just a few items. If you haven't heard of him I strongly recommend at least reading the article I linked. He's a great American genius who is virtually forgotten.

[1] https://en.wikipedia.org/wiki/Charles_Sanders_Peirce