Petrus Crassus was a jurist of the eleventh century, teaching at

Ravenna Ravenna ( , , also ; rgn, Ravèna) is the capital city of the Province of Ravenna, in the Emilia-Romagna region of Northern Italy. It was the capital city of the Western Roman Empire from 408 until its collapse in 476. It then served as the cap ...

. He is known for his treatise ''The Defence of King Henry'' (Latin: ''Defensio Henrici IV'') from 1084 supporting the

Emperor Henry IV Henry IV (german: Heinrich IV; 11 November 1050 – 7 August 1106) was Holy Roman Emperor from 1084 to 1105, King of Germany from 1054 to 1105, King of Italy and Burgundy from 1056 to 1105, and Duke of Bavaria from 1052 to 1054. He was the son ...

against

Pope Gregory VII Pope Gregory VII ( la, Gregorius VII; 1015 – 25 May 1085), born Hildebrand of Sovana ( it, Ildebrando di Soana), was head of the Catholic Church and ruler of the Papal States from 22 April 1073 to his death in 1085. He is venerated as a saint ...

during the

investiture contest The Investiture Controversy, also called Investiture Contest (German: ''Investiturstreit''; ), was a conflict between the Church and the state in medieval Europe over the ability to choose and install bishops (investiture) and abbots of monast ...

. According to the ''

Catholic Encyclopedia The ''Catholic Encyclopedia: An International Work of Reference on the Constitution, Doctrine, Discipline, and History of the Catholic Church'' (also referred to as the ''Old Catholic Encyclopedia'' and the ''Original Catholic Encyclopedia'') i ...

'', he was the only layman involved in the struggle, and supported the autonomy of the state.

Walter Ullmann Walter Ullmann (29 November 1910 – 18 January 1983) was an Austrian-Jewish scholar who left Austria in the 1930s and settled in the United Kingdom, where he became a naturalised citizen. He was a recognised authority on medieval political thou ...

says that the ''Defensio'' is "the first book that employed Roman law in a professional manner and in the service of public government." Joseph Canning writes''A History of Medieval Political Thought'' (1996), p.101.

Peter Crassus' text also formed part of the general theme of Romanism developed among Italian supporters of the
Salian The Salian dynasty or Salic dynasty (german: Salier) was a dynasty in the High Middle Ages. The dynasty provided four kings of Germany (1024–1125), all of whom went on to be crowned Holy Roman emperors (1027–1125). After the death of the l ...
monarchy, as witnessed by
Benzo of Alba Benzo of Alba (died ) was an Italian bishop. He was an opponent of Gregorian reform who supported Henry IV of Germany in the Investiture Controversy. Benzo's date of birth is unknown but he was probably born in northern Italy. Benzo began his caree ...
's ''Liber ad Heinrichum IV.'' (c.1085), with its emphasis on the central role of the emperor as ruler of the world (with Rome its head), 'vicar of the Creator' (''vicarius conditoris'') and maker of popes.

Notes

External links

Contains abridged English text of the DefensioOnline Latin text
11th-century Italian jurists 11th-century Italian writers 11th-century Latin writers {{Italy-law-bio-stub