The origins of what became Dispensationalism lie in John Nelson Darby. As Fitzgerald notes, dividing Scriptural history was not a new idea but what Darby did differently was develop the notion that God had two different plans, one for earthly humans which he called Israel and one for heavenly people, true Christians. This is the origin of the Rapture ideas we’ve become familiar with. Essentially, true Scriptural history has been paused, God will take the true Christians back with Him, and history for Israel will resume to be sorted out. I think you can see how easily this becomes corrupted.