William V, Marquis of Montferrat
William V of Montferrat also known regnally as William III of Montferrat while also referred to as William the Old or William the Elder, in order to distinguish him from his eldest son, William Longsword, was seventh Marquis of Montferrat from 1135 to his death in 1191. William was the only son of Marquis Renier I and his wife Gisela, a daughter of Count William I of Burgundy and widow of Count Humbert II of Savoy. It seems likely, given that he was still fit enough to participate in battle in 1187, that William was one of his parents' youngest children.
He was described by Acerbo Morena as of medium height and compact build, with a round, somewhat ruddy face and hair so fair as to be almost white. He was eloquent, intelligent and good-humoured, generous but not extravagant. Dynastically, he was extremely well connected: a nephew of Pope Callixtus II, a half-brother of Amadeus III of Savoy whose daughter, Matilda, was married to King Afonso I of Portugal, a brother-in-law of Louis VI of France, a cousin of Alfonso VII of Castile, and his maternal great-grandmother was Alice of Normandy which made him a distant relative to the Norman monarchs of England.
Dynastic marriage
William married Judith (or Ita) of Babenberg, daughter of Leopold III of Austria and Agnes of Germany, sometime before March 28, 1133. Judith was probably about 15 at the time. None of their surviving children seem to have been born before 1140, and the youngest son was born in 1162. She died after 1168. They had five sons, four of whom became prominent in the affairs of the Kingdom of Jerusalem and of Byzantium:- William Longsword, Count of Jaffa and Ascalon, father of Baldwin V of Jerusalem
- Conrad, King of Jerusalem
- Boniface, his successor to Montferrat and founder of the Kingdom of Thessalonica
- Frederick, who entered the Church and became Bishop of Alba.
- Renier, married into the Byzantine imperial family
- Agnes, who married Count Guido Guerra III Guidi conte di Modigliana. The marriage was annulled on grounds of childlessness before 1180, when Guido remarried, and Agnes entered the convent of Santa Maria di Rocca delle Donne.
- Adelasia, or Azalaïs, who married Manfred II, Marquis of Saluzzo, c. 1182, and was regent for her grandson Manfred III.
- An unidentified daughter, who married Albert, Marquis of Malaspina.
Otto of Tonengo, who became Bishop of Porto, and Cardinal in 1227, has sometimes been identified as a son of William V, and confused with Frederick. However, his dates make it more likely that he was a son of William VI of Montferrat, whether legitimate or not is uncertain.
William and Judith's powerful dynastic connections created difficulties in finding suitable wives for his sons, and too many potential spouses were related within prohibited degrees. In 1167, he unsuccessfully tried to negotiate marriages for his eldest sons to daughters of Henry II, King of England—but the girls were very young at the time and were related through Judith's descent from William V of Aquitaine. He then applied for sisters of William I, King of Scotland, who were not related, but were already married.
Alliances with the Western and Eastern Empires
William took part in the Second Crusade, alongside his half-brother Amadeus of Savoy, his nephew Louis VII of France, his brother-in-law Count Guido of Biandrate, and his wife's German and Austrian relatives.As supporters of the imperial party, he and his sons fought with the Emperor Frederick Barbarossa in his lengthy struggle against the Lombard League. Following Barbarossa's capitulation with the Peace of Venice in 1177, William was left to deal with the rebellious towns in the area alone. Meanwhile, the Byzantine emperor Manuel I Komnenos sought support for his own politics in Italy.
William broke with Barbarossa and formed an alliance with Manuel. His eldest surviving son, Conrad, was taken prisoner by Barbarossa's chancellor, Archbishop Christian of Mainz, but then captured the chancellor in battle at Camerino. In 1179 Manuel suggested a marriage between his daughter Maria, second in line to the throne, and one of William's sons. As Conrad and Boniface were already married, the youngest son, Renier, was married off to the princess, who was ten years his senior. Renier and Maria were later killed during the usurpation of Andronikos, and the family rebuilt ties with Barbarossa.