History of Sound Questions

In terms of the history of sound at the movies, I would like to learn more about...
1.When did films transition from musical scores to actually having dialogue and sound effects?
2. In what era did foley start and how was it first received?
Of the majority of early films we've seen, they only have music in the background or no sound at all, so I'm curious about when films started to incorporate dialogue. I know that slates on the screen had been used in the early silent film to show someone's words or thoughts, but I think that actually having audio with the actor's voices would make it easier to tell stories. Also, I'm fascinated by the work of foley artists and their role now in Hollywood, and I'd like to learn when and how they got their start in the industry. I feel like that position is something people might've looked down upon, as it involves using everyday objects and doesn't fit the glamorous jobs that people usually associate with movies. With that said, I'd like to learn about some of the earliest foley artists, and get a sense for their stories and opinions on the industry back then.