William of Capraia was the regent for Marianus II of Arborea

Marianus II of Arborea

Marianus II was the Giudici of Arborea from 1241 to his death. With skilled military action, he came to control more than half of the island of Sardinia...

 from 1241 until his death, being entitled "Judge" from 1250 on.

Biography

He was the son of Ugo degli Alberti of the Counts of Capraia and Bina, the first wife of Peter I of Arborea

Peter I of Arborea

Peter I , of the Serra family, was the eldest son and successor of Barisone II of Arborea, reigning from 1186 to his death. His mother was Barisone's first wife, Pellegrina de Lacon...

, whom he divorced in 1191 and who subsequently remarried (1193).

When Peter II of Arborea

Peter II of Arborea

Peter II was the Giudice of Arborea from 1221 to his death. He was also Peter IV, Viscount of Bas. He was "pious and submissive to the church" and his extensive "donations of privileges and judicial lands impoverished his state of glory."Peter's father, Hugh I, of the Bas family, died in 1211...

 died in 1241, William immediately assumed the regency with the alliance of the Gherardeschi, counts of Donoratico, and the Visconti

House of Visconti

Visconti is the family name of two important Italian noble dynasties of the Middle Ages. There are two distinct Visconti families: The first one in the Republic of Pisa in the mid twelfth century who achieved prominence first in Pisa, then in Sardinia where they became rulers of Gallura...

. On 29 September 1250, Pope Innocent IV

Pope Innocent IV

Pope Innocent IV , born Sinibaldo Fieschi, was pope from June 25, 1243 until his death in 1254.-Early life:...

 recognised his sovereignty in Arborea, though the Corona de Logu never did.

In 1257, William led Arborea, along with Gallura

Giudicato of Gallura

The Giudicato of Gallura was one of four Sardinian giudicati of the Middle Ages. These were de facto independent states ruled by judges bearing the title iudex . Gallura, a name which comes from gallus, meaning rooster , was subdivided into ten curatoriae governed by curatores under the judge...

 and Logudoro, the Pisan

Republic of Pisa

The Republic of Pisa was a de facto independent state centered on the Tuscan city of Pisa during the late tenth and eleventh centuries. It rose to become an economic powerhouse, a commercial center whose merchants dominated Mediterranean and Italian trade for a century before being surpassed and...

 giudicati, into a war against Genoese

Republic of Genoa

The Most Serene Republic of Genoa |Ligurian]]: Repúbrica de Zêna) was an independent state from 1005 to 1797 in Liguria on the northwestern Italian coast, as well as Corsica from 1347 to 1768, and numerous other territories throughout the Mediterranean....

 Cagliari

Giudicato of Cagliari

The Giudicato of Cagliari was one of the four Sardinian giudicati of the Middle Ages. It covered the entire south and central east portion of the island and was composed of thirteen subdivisions called curatoriae. To its north and west lay Arborea and north and on the east lay Gallura and Logudoro...

. After fourteen months of war, the deposed judge of Cagliari, Salusio VI

William III of Cagliari

William III, of the House of Massa, was the last Judge of Cagliari, ruling under the name Salusio VI from 1256 to his deposition in 1258. He is known also known as Guglielmo Cepolla or Cipolla....

, was forced to flee and his giudicato was divided up between the victors: a third to Gallura, a third to Arborea, and a third to the Gherardeschi of Pisa. Salusio's capital, Santa Igia

Santa Igia

Santa Igia was a city in Sardinia, in what is now Italy, which existed from the 9th century AD to 1258, when it was destroyed by the Pisane troops...

, was destroyed. Ogliastra and Sarrabus went to John Visconti of Gallura, while the curatori of Gippi, Nuraminis

Nuraminis

Nuraminis is a comune in the Province of Cagliari in the Italian region Sardinia, located about 25 km northwest of Cagliari...

, Trexenta

Trexenta

Trexenta is a traditional subregion of Sardinia, Italy, located in the northern part of the province of Cagliari. It encompasses an area of c. 400 km², including 13 municipalities....

, Marmilla inferiore, Dolia

Dolia

Dolia can refer to:*A synonym for Nolana*One of the Slavic fairies...

, Gerrei, and Barbagia di Seulo

Barbagia di Seulo

The Barbagia di Seulo is a historical subregion of central-eastern Sardinia, Italy. It includes the communes of Seulo, Seui, Sadali, Esterzili and Ussassai....

 went to Arborea. Sulcis

Sulcis

Sulcis is the southwestern region of Sardinia, part of the larger Sulcis-Iglesiente region. It is named for the Phoenician city of Sulcis , present-day Sant'Antioco....

, Cixerri

Cixerri

The Cixerri is an Italian river in southern Sardinia province of Cagliari. It springs from Monte Croccoriga, at 313 m above sea level, in the province of Carbonia-Iglesias. The river flows into a lake north of Iglesias and then exist the lake and flows eastward. The river is joined by a...

, Nora

Nora

Nora or Norah may refer to:*Nora , an English and Irish feminine personal name* Nóra , a Hungarian feminine personal name-People:*Nora Aunor, a multi-awarded Filipino actress-singer-producer*Norah Baring, a British movie actress...

, and Decimo were granted to Gherardo and Ugolino della Gherardesca

Ugolino della Gherardesca

Count Ugolino della Gherardesca , count of Donoratico, was an Italian nobleman, politician and naval commander. He was frequently accused of treason and features prominently in Dante's Divine Comedy.-Biography:...

, counts of Donoratico, while Cagliari itself went to the commune of Pisa. By its expansion into the interior of the island, Arborea ensured its long-term survival in the face of external foes.

Next, William pressed his claims to Logudoro — derived from Hugh I of Arborea

Hugh I of Arborea

Hugh I Giudici of Arborea from 1185 CE until his death in 1211 CE. Hugh was the son of Ispella di Serra and Hugh I of Bas. He was a grandson -through his mother- of Barisone II of Arborea...

, who was a uterine brother of Marianus II of Logudoro — by arms. In 1259, he entered into a lifelong battle with the Doria

Doria

Doria, originally de Auria , meaning "the sons of Auria", and then de Oria or d'Oria, is the name of an old and extremely wealthy Genoese family who played a major role in the history of the Republic of Genoa and in Italy, from the 12th century to the 16th century.-Origins:According to legend, a...

 of Genoa after the death of Adelasia

Adelasia of Torres

Adelasia , eldest child of Marianus II of Logudoro by Agnes of Massa, daughter of William I of Cagliari, and successor of her brother, Barisone III, in 1236, was the Judge of Logudoro from 1236 and Judge of Gallura from 1238....

, the last ruler of the native dynasty in Logudoro.

When he died in 1264, William left the regency-judgeship to his son Nicholas.