In late 1114, Henry V (not that one, the Frankish version) the Holy Roman Emperor, invaded the Duchy of Saxony to assert his authority on Duke Lothair of Supplinsburg. Lothair was the Pope’s ally in the Investiture Controversy and supported the Pope’s demands to appoint local church officials. More practically, Lothair despised Henry’s heavy handed ways. Henry was a direct descendant of Charlemagne and believed he was a Roman Emperor no different than Nero, Augustus, or Marcus Aurelius.
On 11 February 1115, Lothair’s Saxon army met Henry’s Imperial army just outside the town of Welfesholz (in modern day Saxon-Anhalt, Germany). The Imperial Army was led by Henry’s field marshal, Count Hoyer of Mansfeld. The Imperial Army was defeated when a young knight slew Mansfeld in single combat during the battle. The Imperial Army army routed after witnessing Mansfeld’s death.
The battle effectively broke Imperial power and ended the destructive 50 year long “civil war” between medieval Germans that had stalled Central Europe politically and culturally. More importantly, the Battle of Welfesholz forced Henry, at the Concordant of Worms in 1122, to accept the Papal investiture of bishops in the Holy Roman Empire, and soon, all of Christendom.
Up to this point in the Middle Ages, Imperial dukes, counts, and princes relied on the bishops and clergy for the administration of their territories. Since the clergy had to be literate (to read the Bible) and Imperial nobility could appoint them, it made sense to have the loyal clergy administer the Empie. But after the Battle of Welfesholz and Concordant of Worms, the Empire’s administration was no longer solely loyal to the Emperor and his princes. The new Papal influence on bishops forced the Imperial nobility to create their own administrations separate from the clergy. A loyal secular administration demanded an increase in literacy among the population to fill the vacuum left by the potentially divided loyalties of the clerical (religious) staff.
The ability to appoint bishops greatly increased Papal and monastic influence across Europe and elevated members of the lower classes to unheard of power and glory in the process as Papal appointed clergy. And the nobility’s inability to appoint clergy in their realms meant a vast increase in noble military aged males with nothing to do. Where once they’d be chosen as priests and bishops, they now became barons, knights, or mercenaries. This massive influx of fighting men pushed feudalism to its natural limits and the Imperial lands became a patchwork of robber baronies and petty kingdoms that raided and warred upon each other.