+**840** was a [year](/wiki/Year) in the [Julian calendar](/wiki/Julian_calendar), marked by key shifts in power across Europe. It witnessed events that would influence the trajectory of the early [Middle Ages](/wiki/Middle_Ages).
+## See also
+- [9th Century](/wiki/9th_Century)
+- [Carolingian Empire](/wiki/Carolingian_Empire)
+- [Louis the Pious](/wiki/Louis_the_Pious)
... 1 more lines