became daunting if not impossible during and after the Muslim conquest of Sicily between 827 and 902. A letter by Pope Nicholas I as early as 864 mentions the "Sardinian judges", without reference to the empire and a letter by Pope John VIII (reigned 872–882) refers to them as principes ("princes"). By the time of De Administrando Imperio, completed in 952, the Byzantine authorities no longer listed Sardinia as an imperial province, suggesting they considered it lost. In all likelihood a local noble family, the Lacon-Gunale, acceded to the power of Archon, still identifying themselves as vassals of the Byzantines, but de facto independent as communications with Constantinople were very difficult. Only two names of those rulers are known: Salusios () and the protospatharios Turcoturios () from two inscriptions), who probably reigned between the 10th and the 11th century. These rulers were still closely linked to the Byzantines, both for a pact of ancient vassalage, and from the ideological point of view, with the use of the Byzantine Greek language (in a Romance country), and the use of art of Byzantine inspiration. In the early 11th century, an attempt to conquer the island was made by the Moors based in the Iberian Peninsula. The only records of that war are from Pisan and Genoese chronicles. The Christians won but, after that, the previous Sardinian kingdom was undermined and subsequently divided into four smaller states: Cagliari (Calari), Arborea (Arbaree), Gallura, and Torres or Logudoro. Whether this final transformation from imperial civil servant to independent sovereign bodies resulted from imperial abandonment or local assertion, by the 10th century, the so-called "Judges" ( / , a Byzantine administrative title) had emerged as the autonomous rulers of Sardinia. The title of changed with the language and local understanding of the position, becoming the Sardinian , essentially a king or sovereign, while Judicate () came to mean 'state'. Early medieval Sardinian political institutions evolved from the millennium-old Roman imperial structures with relatively little Germanic influence. Although the Judicates were hereditary lordships, the old Byzantine imperial notion that personal title or honor was separate from the state still remained, so the Judicate was not regarded as the personal property of the monarch as was common in later European feudalism. Like the imperial systems, the new order also preserved "semi-democratic" forms, with national assemblies called the Crown of the Realm. Each Judicate saw to its own defense,