Since the
Battle of Las Navas de Tolosa in 1212 halted the advance of the
Almohads in Spain, a series of truces had kept Castile and the Almohad dominions of
al-Andalus more-or-less at peace. However, a crisis of succession in the Almohad Caliphate after the death of
Yusuf II in 1224 gave Ferdinand III an opportunity for intervention. The Andalusian-based claimant,
Abdallah al-Adil, began to ship the bulk of Almohad arms and men across the
straits to
Morocco to contest the succession with his rival there, leaving al-Andalus relatively undefended. Al-Adil's rebellious cousin, Abdullah al-Bayyasi (the
Baezan), appealed to Ferdinand III for military assistance against the usurper. In 1225, a Castilian army accompanied al-Bayyasi in a campaign,
ravaging the regions of
Jaén,
vega de Granada and, before the end of the year, had successfully installed al-Bayyasi in
Córdoba. In payment, al-Bayyasi gave Ferdinand the strategic frontier strongholds of
Baños de la Encina, Salvatierra (the old
Order of Calatrava fortress near
Ciudad Real) and
Capilla (the last of which had to be taken by siege). When al-Bayyasi was rejected and killed by a popular uprising in Córdoba shortly after, the Castilians remained in occupation of al-Bayyasi's holdings in
Andújar,
Baeza and
Martos. The crisis in the Almohad Caliphate, however, remained unresolved. In 1228, a new Almohad pretender,
Idris al-Ma'mun, decided to abandon Spain, and left with the last remnant of the Almohad forces for Morocco. Al-Andalus was left fragmented in the hands of local strongmen, only loosely led by
Muhammad ibn Yusuf ibn Hud al-Judhami. Seeing the opportunity, the Christian kings of the north – Ferdinand III of Castile,
Alfonso IX of León,
James I of Aragon and
Sancho II of Portugal – immediately launched a series of raids on al-Andalus, renewed almost every year. There were no great battle encounters – Ibn Hud's makeshift Andalusian army was destroyed early on, while attempting to stop the Leonese at
Alange in 1230. The Christian armies romped through the south virtually unopposed in the field. Individual Andalusian cities were left to resist or negotiate their capitulation by themselves, with little or no prospect of rescue from Morocco or anywhere else. The twenty years from 1228 to 1248 saw the most massive advance in the
reconquista yet. In this great sweep, most of the great old citadels of al-Andalus fell one by one. Ferdinand III took the lion's share of the spoils –
Badajoz and
Mérida (which had fallen to the Leonese), were promptly inherited by Ferdinand in 1230; then by his own effort,
Cazorla in 1231,
Úbeda in 1233, the old
Umayyad capital of
Córdoba in 1236,
Niebla and
Huelva in 1238,
Écija and
Lucena in 1240,
Orihuela and
Murcia in 1243 (by the famous 'pact of Alcaraz'),
Arjona,
Mula and
Lorca in 1244,
Cartagena in 1245,
Jaén in 1246,
Alicante in 1248 and finally, on 22 December 1248, Ferdinand III entered as a conqueror in
Seville, the greatest of Andalusian cities. At the end of this twenty-year onslaught, only a rump Andalusian state, the
Emirate of Granada, remained unconquered (and even so, Ferdinand III managed to extract a tributary arrangement from Granada in 1238). Ferdinand annexed some of his conquests directly into the
Crown of Castile, and others were initially received and organized as vassal states under Muslim governors (e.g. Alicante, Niebla, Murcia), although they too were eventually permanently occupied and absorbed into Castile before the end of the century (Niebla in 1262, Murcia in 1264, Alicante in 1266). Outside of these vassal states, Christian rule could be heavy-handed on the new Muslim subjects. The range of Castilian conquests also sometimes transgressed into the spheres of interest of other conquerors. Thus, along the way, Ferdinand III took care to carefully negotiate with the other Christian kings to avoid conflict, e.g. the
treaty of Almizra (26 March 1244) which delineated the Murcian boundary with
James I of Aragon. Ferdinand divided the conquered territories between the
Knights, the Church, and the nobility, whom he endowed with great
latifundia. When he took Córdoba, he ordered the
Liber Iudiciorum to be adopted and observed by its citizens, and caused it to be rendered, albeit inaccurately, into
Castilian. The capture of Córdoba was the result of a well-planned and executed process whereby parts of the city (the Ajarquía) first fell to the independent
almogavars of the
Sierra Morena to the north, which Ferdinand had not at the time subjugated. Only in 1236 did Ferdinand arrive with a royal army to take the Medina, the religious and administrative centre of the city. Ferdinand set up a council of
partidores to divide the conquests and between 1237 and 1244 a great deal of land was parcelled out to private individuals and members of the royal family as well as to the Church. On 10 March 1241, Ferdinand established seven outposts to define the boundary of the province of Córdoba. Following his conquest of Cordoba, Pope Gregory IX hailed Ferdinand as an "athleta Christi"(champion of Christ) and ordered bishops in Castile and Leon to provide him with 20,000 gold pieces a year, for three years. == Domestic policy ==