Alexios V Doukas, surnamed Mourtzouphlos (Greek: Ἀλέξιος Δούκας Μούρτζουφλος, d. December 1205, Constantinople) was Byzantine Emperor (5 February – 12 April 1204) during the second and final siege of Constantinople by the participants of the Fourth Crusade. He was related to the imperial Doukas family.

His nickname "Mourtzouphlos" referred to either his bushy, overhanging eyebrows or his sullen character. The term has the meaning of one being crestfallen, depressed, despondent, downcast, gloomy, sullen and evidently frowning, scowling.

A Byzantine nobleman, he had risen to the court position of protovestiarios by the time of the Fourth Crusade. He had been married twice but was now allegedly the lover of Eudokia Angelina, a daughter of Emperor Alexios III Angelos. His participation in the attempted usurpation of John Komnenos the Fat in 1200 had caused him to be imprisoned until the accession of Isaac II Angelos, who was restored to the throne after having been deposed and imprisoned by his brother Alexios III, and his son Alexios IV Angelos, who were placed on the throne by the intervention of the Fourth Crusade in July 1203.

Balian of Ibelin (French: Balian d'Ibelin; early 1140s–1193) was an important French noble in the crusader Kingdom of Jerusalem in the 12th century.

Balian was the youngest son of Barisan of Ibelin, and brother of Hugh and Baldwin. His father, a knight in the County of Jaffa, had been rewarded with the lordship of Ibelin after the revolt of Hugh II of Le Puiset. Barisan married Helvis of Ramla, heiress of the wealthy lordship of Ramla. Balian's name was also Barisan, but he seems to have adapted the name (found in Tuscany and Liguria) to the Old French "Balian" c. 1175–76; he is sometimes known as Balian the Younger or Balian II when his father is also referred to as Balian. He is also called Balian of Ramla or Balian of Nablus. In Latin his name appears variously as Balian, Barisan, Barisanus, Balianus, Balisan, and Balisanus. Arabic sources call him Balian ibn Barzan', which translates "Balian, son of Barzan (or Barisan). His precise year of birth is unknown, but he was of the age of majority (usually 15) by 1158, when he first appears in charters, having been described as under-age ("infra annos") in 1155.