Much is said about Henry IV's humiliating himself at Canossa. In fact, his humiliation
was a subterfuge, and he later huniliated Gregory VII even worse.
"he pope promptly excommunicated Henry and released his subjects from their oath of loyalty to him. To keep his crown, Henry cleverly sought the pope at Canossa in the Apennines in January 1077, where, after three days of humble penitence, he was forgiven. The princes, however, elected a rival king, Rudolf of Swabia. The result was nearly 20 years of civil war. In 1080 Gregory excommunicated Henry again and recognized Rudolf. Deposing Gregory, Henry marched on Rome, installed the antipope Clement III, and was crowned emperor in 1084. Henry returned to Germany to continue the civil war against a new rival king (Rudolf had died in 1080). Finally, betrayed and imprisoned by his son Henry, the emperor was forced to abdicate."

"Germany, Federal Republic of," Microsoft(R) Encarta(R) 98 Encyclopedia. (c) 1993-1997 Microsoft Corporation. All rights reserved.

From The Story of Civilization, Vol. IV, The Age of Faith, by Will & Ariel Durant, p. 557:
"Pope Gregory went on to Salerno held another synod, excommunicated Henry again,
and then broke down in body and spirit. " I have loved righteousness in spirit," he said,
" and hated iniquity: therefore I die in exile." He was only sixty two; but the nervous strain
of his bitter controversies had worn him out; and his apparent defeat by the man whom he
had forgiven a Canossa left him no will to live."

In other words, "Going to Canossa" was not a lasting humiliation, it was a subterfuge to
survive politically, until Henry IV could crush Gregory VII. The Church manages to play that
part down.