Peninsula stopped in Murcia, which eventually consolidated as a realm of the Crown of Castile, the Kingdom of Murcia. Subsequently, the Aragonese Crown focused on the Mediterranean, governing as far afield as Greece and the Barbary Coast, whereas Portugal, which completed its southward expansion in 1249, would focus on the Atlantic Ocean. Mercenaries from the territories in the Crown, known as Almogavars participated in the creation of this Mediterranean empire, and later found employment in countries all across southern Europe. The Crown of Aragon has been considered an empire which ruled in the Mediterranean for hundreds of years, with thalassocratic power to setting rules over the entire sea, (as documented, for instance, in the Llibre del Consolat del Mar or Book of the Consulate of the Sea, written in Catalan, is one of the oldest compilations of maritime laws in the world). However, the different territories were only connected through the person of the monarch, an aspect of empire seen as early as Achaemenid Persia. A modern historian, Juan de Contreras y Lopez de Ayala, Marqués de Lozoya described the Crown of Aragon as being more like a confederacy than a centralised kingdom. Origin The Crown of Aragon originated in 1137, when the Kingdom of Aragon and the County of Barcelona (along with the County of Provence, Girona, Cerdanya, Osona and other territories) merged by dynastic union upon the marriage of Petronilla of Aragon and Raymond Berenguer IV of Barcelona; their individual titles combined in the person of their son Alfonso II of Aragon, who ascended to the throne in 1162. This union respected the existing institutions and parliaments of both territories. The combined state was initially known as Regno, Dominio et Corona Aragonum et Catalonie, and later as Corona Regum Aragoniae, Corona Aragonum or simply Aragon. Petronilla's father King Ramiro, "The Monk" (reigned 1134–1137) who was raised in the Monastery of Saint Pons de Thomières, Viscounty of Béziers as a Benedictine monk was the youngest of three brothers. His brothers Peter I (reigned 1094–1104) and Alfonso I El Batallador (The Battler, reigned 1104–1134) had bravely fought against Castile for hegemony in the Iberian peninsula. Upon the death of Alfonso I, the Aragonese nobility that campaigned close to him feared being overwhelmed by the influence of Castile. And so, Ramiro was forced to leave his monastic life and proclaim himself King of Aragon. He married Agnes, sister of the Duke