When was the OT canon as used by Protestants finalized? At what date (and/or event) was the Old Testament canon currently recognized by most Protestants finalized? What is the earliest occurrence we have of it being referenced in it's current form and who (or what event) announced it as finalized?
According to Talmud, the Tanakh canon (Protestant OT) was compiled in 450 BC, but modern scholars describe the development of the canon as a process occurring between 200 BC to 200 AD. First the Torah, then the Nevi'im, and then the latest is the Ketuvim.