Dietrich von Hildebrand (October 12, 1889 – January 26, 1977) was a German Catholic philosopher and theologian who was called (informally) by Pope Pius XII "the 20th Century Doctor of the Church."

Pope John Paul II greatly admired the work of von Hildebrand, remarking once to von Hildebrand's widow, Alice von Hildebrand, "Your husband is one of the great ethicists of the twentieth century." Pope Benedict XVI has a particular admiration and regard for Dietrich von Hildebrand, whom he already knew as a young priest in Munich. In the 1950s and 1960s, von Hildebrand frequented the church of St. Georg in Munich, where the young Fr. Josef Ratzinger served as assistant pastor. It was also in St. Georg that Dietrich and Alice von Hildebrand were married. The degree of Pope Benedict's esteem is expressed in one of his statements about von Hildebrand, "When the intellectual history of the Catholic Church in the twentieth century is written, the name of Dietrich von Hildebrand will be most prominent among the figures of our time." Von Hildebrand was a vocal critic of the changes in the church brought about after the Second Vatican Council, in particular those to the liturgy. Of them he said "Truly, if one of the devils in C.S. Lewis' The Screwtape Letters had been entrusted with the ruin of the liturgy, he could not have done it better."

Hildebrand is a character from Germanic legend. Hildebrand is the modern German form of the name: in Old High German it is Hiltibrant and in Old Norse Hildibrandr. The word hild means "battle" and brand means "sword". The name itself is very likely of Langobard origin.

He is associated with the cycle of legends about Theodoric the Great, called Dietrich in German, to whom he is a companion. Hildebrand figures in three famous songs: in the Old High German Hildebrandslied, the Middle High German Nibelungenlied, and in the Old Norse song Hildebrand's death in Ásmundar saga kappabana (called Hildibrandr). He also appears as Hildiger in Gesta Danorum.

In the Nibelungenlied, he is the armourer, brother-in-arms and fatherly friend of Dietrich von Bern. It is he that kills Kriemhild, after she ordered her brother's death and killed Hagen herself.

In the Hildebrandslied, which is older, Hildebrand fights his own son Hadubrand. In fact Hildebrand became Dietrich's armourer, because he had to leave his home, he left his wife and his son. 30 years later, Hildebrand returns. His son Hadubrand is now ruling over his land, he is leading his army against the supposed invasion. As is customary, the two leaders meet between the armies. They start to list their family tree, in order to prevent themselves from killing a relative. Hadubrand says that he is "Hadubrand Hildebrand's son", but he was told that Hildebrand died, and he thinks that the fighter before him is using Hildebrand's name to deceive him. In fact in the original text with the end of the song is lost, but the legends and the third song tell the end of the story. Hildebrand has to kill his son otherwise he would be killed by him; he has pictures of all the warriors he killed on his red shield, and his son's picture is added to the others.