There are many fictional verses
with their own timeline and history, some longer, some shorter. Then comes along an adaptation which makes changes to the estabilshed timeline: it shortens or expands timespans, switches dates and events or pulls them forward or backwards in time.
Can lead to (un)acknowledged butterfly effects
and Adaptation Induced Plot Holes
if not done careful.
Is related to and can also function as an umbrella to more specific adaptional change tropes
, Adaptation Induced Plot Hole
- The Hobbit: Seems to have changed dates quite a bit with dwarven history and the White Council's fight against the Necromancer.