Henry IV (November 11, 1050 – August 7, 1106) was King of Germany from 1056 and Emperor from 1084, until his abdication in 1105. He was the third emperor of the Salian dynasty.

Henry was the eldest son of the Emperor Henry III, by his second wife Agnes de Poitou, and was probably born at the royal palace at Goslar. His christening was delayed until the following Easter so that Abbot Hugh of Cluny could be one of his godparents. But even before that, at his Christmas court Henry III induced the attending nobles to promise to be faithful to his son. Three years later, still anxious to ensure the succession, Henry III had a larger assembly of nobles elect the young Henry as his successor, and then, on July 17, 1054, had him crowned as king by Archbishop Herman of Cologne. Thus when Henry III unexpectedly died in 1056, the accession of the 6-year-old Henry IV was not opposed. The dowager Empress Agnes acted as regent. Henry's reign was marked by efforts to consolidate Imperial power. In reality, however, it was a careful balancing act between maintaining the loyalty of the nobility and the support of the pope. Henry jeopardized both when, in 1075, his insistence on the right of a secular ruler to invest, i.e., to place in office, members of the clergy, especially bishops, began the conflict known as the Investiture Controversy. In the same year he defeated a rebellion of Saxons in the First Battle of Langensalza. Pope Gregory VII excommunicated Henry on February 22, 1076. Gregory, on his way to a diet at Augsburg, and hearing that Henry was approaching, took refuge in the castle of Canossa (near Reggio Emilia), belonging to Matilda, Countess of Tuscany. Henry's intent, however, was to perform the penance required to lift his excommunication, and ensure his continued rule. He stood for three days, January 25 to January 27, 1077, outside the gate at Canossa in the snow, begging the pope to rescind the sentence (popularly portrayed as without shoes, taking no food or shelter, and wearing a hairshirt). The Pope lifted the excommunication, imposing a vow to comply with certain conditions, which Henry soon violated.

In his last years Henry faced rebellions from his eldest son and his wife. He died at Liège in 1106, "like one falling asleep", after nine days of illness. He was interred next to his father at Speyer.

In 1055 Henry was betrothed to Bertha of Maurienne, daughter of Count Otto of Savoy. They were married in June 1066. In 1068 he attempted to divorce her, but was unable and Bertha was restored as Empress a year later. She died on December 27, 1086 and was buried at the cathedral of Speyer. Their children were:
1. Agnes of Germany (born 1072/1073), married Frederick I von Staufen, Duke of Swabia.
2. Conrad (February 12, 1074-July 27, 1101)
3. Adelaide, died in infancy
4. Henry, died in infancy
5. Henry (1086)

In 1089 Henry married Eupraxia of Kiev, the only daughter of Vsevolod I, Prince of Kiev, and sister to his son Vladimir Monomakh (1053 -- May 19, 1125), prince of Kievan Rus. She assumed the name "Adelaide" upon her coronation. In 1094 she joined a rebellion against him, accusing Henry of holding her prisoner; of forcing her to participate in orgies; and attempting a black mass on her naked body.