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Henry IV, like his father before him, was the son and heir of his father, continuing a dynasty. At age six, he became Holy Roman Emperor through his mother, the Empress Agnes, who was his Regent.
Unlike his father, Henry IV literally grew up in the role of being Holy Roman Emperor. He had no real, outside leadership experience, certainly his mother, the Empress Agnes, taught him nothing. In fact, duringher regency, the position of Holy Roman Emperor lost much of the power that Henry III had managed to accrue for it.
So, Henry IV grew up in the position. Also unlike his father, he was not particularly sympathetic or considerate of the "growing pains" the Latin Church was experiencing--he chose instead to focus on regaining the powers that Holy Roman Emperors had formerly enjoyed.
This would ultimately lead to a confrontation between Henry IV, and Gregory VII, also known as Hildebrand, in The Struggle for Power.