Following the failure of the January 1, 1000 prediction, some theorists proposed that the end would occur 1000 years after Jesus death, instead of his birth.
"Many authorities who had loudly proclaimed that the world would definitely end in the year 1000 explained their obvious miscalculation by "realising" they should have added Jesus' life span to their prediction. As a result, the world would now reliably end in 1033"
Browne, Silvia (2008). End of Days: Predictions and Prophecies About the End of the World. Dutton Penguin