Eustace the Monk was a mercenary

Mercenary

A mercenary, is a person who takes part in an armed conflict based on the promise of material compensation rather than having a direct interest in, or a legal obligation to, the conflict itself. A non-conscript professional member of a regular army is not considered to be a mercenary although he...

 and pirate

Piracy

Piracy is an act of robbery or criminal violence at sea. The term can include acts committed on land, in the air, or in other major bodies of water or on a shore. It does not normally include crimes committed against persons traveling on the same vessel as the perpetrator...

, in the tradition of medieval

Middle Ages

The Middle Ages is a periodization of European history from the 5th century to the 15th century. The Middle Ages follows the fall of the Western Roman Empire in 476 and precedes the Early Modern Era. It is the middle period of a three-period division of Western history: Classic, Medieval and Modern...

 outlaws.
Eustace was born a younger son of Baudoin Busket, a lord of the county of Boulogne

Boulogne-sur-Mer

-Road:* Metropolitan bus services are operated by the TCRB* Coach services to Calais and Dunkerque* A16 motorway-Rail:* The main railway station is Gare de Boulogne-Ville and located in the south of the city....

. According to his biography, he went to Toledo

Toledo, Spain

Toledo's Alcázar became renowned in the 19th and 20th centuries as a military academy. At the outbreak of the Spanish Civil War in 1936 its garrison was famously besieged by Republican forces.-Economy:...

, Spain

Spain

Spain , officially the Kingdom of Spain languages]] under the European Charter for Regional or Minority Languages. In each of these, Spain's official name is as follows:;;;;;;), is a country and member state of the European Union located in southwestern Europe on the Iberian Peninsula...

, studied black magic

Black magic

Black magic is the type of magic that draws on assumed malevolent powers or is used with the intention to kill, steal, injure, cause misfortune or destruction, or for personal gain without regard to harmful consequences. As a term, "black magic" is normally used by those that do not approve of its...

 there, returned home to become a Benedictine

Benedictine

Benedictine refers to the spirituality and consecrated life in accordance with the Rule of St Benedict, written by Benedict of Nursia in the sixth century for the cenobitic communities he founded in central Italy. The most notable of these is Monte Cassino, the first monastery founded by Benedict...

 monk at St Samer Abbey near Calais

Calais

Calais is a town in Northern France in the department of Pas-de-Calais, of which it is a sub-prefecture. Although Calais is by far the largest city in Pas-de-Calais, the department's capital is its third-largest city of Arras....

, and then left the monastery to avenge his murdered father. Other evidence, however, suggests that his father's death occurred soon after 1190.