The 12th-century English chronicler Gervase of Canterbury recorded what may be one of the earliest European accounts of ball lightning in his historical works. Writing during the reign of King Henry II, Gervase described luminous phenomena observed during thunderstorms that closely match modern ball lightning descriptions: spheres of light that descended from storm clouds, moved along the ground or through buildings, and sometimes caused fires or injuries. Medieval chroniclers like Gervase did not have the vocabulary or conceptual framework to describe atmospheric electrical phenomena in scientific terms, instead interpreting them through the lens of divine intervention, demonic activity, or portents. Gervase's accounts are valuable precisely because they predate any theoretical framework for ball lightning — the descriptions are purely observational, uncontaminated by expectations about what the phenomenon 'should' look like.
The consistency between Gervase's 12th-century observations and modern eyewitness accounts separated by over 800 years suggests that ball lightning has been a stable atmospheric phenomenon throughout recorded history.