According to websters-online-dictionary.com, the word "soliloquy" was first used in 1613. It refers to a dramatic speech spoken by an actor to no one in particular, like talking aloud to yourself.

Who first used soliloquy?

What's interesting about the history of soliloquies, though is that according to one online etymology dictionary, Shakespeare may well have been the first one to adapt the monologue (which is a speech the character gives on stage as part of the accepted action) as a window for the audience to see into the character's ...

Where did soliloquies originate?

soliloquy (n.)

1610s, from Late Latin soliloquium "a talking to oneself," from Latin solus "alone" (see sole (adj.)) + loqui "to speak" (from PIE root *tolkw- "to speak").