No one before 1820 believed this was post-tribulation. The Scriptures speaks only of the pre-tribulation event and the word translated into English as "rapture" is associated, in its roots in Greek, with the 'resurrection of the dead."
We who are alive and remain shall be CAUGHT UP is the resurrection of the dead????? Context says not.
You have pre and post reversed. The misapplication of St. Paul's description of the events living believers will experience at the time of the General Resurrection to an event before the horror of the end-times sketch prophetically in St. John's Apocalypse to promulgate a notion of 'pre-tribulation' rapture, dates to the 1820's.