I'll show you a BLARING retcon, in the realm of religion !
In a book I have by Charles Taze Russell, the founder of the Jehovah's Witnesses, he says "how long before 1914, the 144,000 will be gathered in...". He died in 1918, but, before his death, he changed that doctrinal statement to "How long AFTER 1914...", because Christ failed to move when expected. My copy reflects that rewriting. The last volume was pulled from publication because none of its prophecies panned out.
The Witnesses have to repeatedly readjust their doctrinal timing because predictions kept failing. They also had no call to state that the First Resurrection began in 1918, with the saints being raised from the dead as invisible spirits. They have no proof of this. No more than the Adventists can claim that Christ began the Investigative Judgement in 1844 (He should have ENDED such in 1844 !).
Far too much time has elapsed since the time of Christ - he probably never existed....