Research Notes:

The Chronicon Domini Joannis Emmanuelis records the birth in Aug 1311 of “Dns Alfonsus Rex, filius Dni Fernandi in Salmantica”. The Crónica del Rey Fernando IV records the birth 13 Aug of “[el] infante don Alfonso su fijo primero heredero” to “la reina doña Constanza”, dated to 1311.

He succeeded his father in 1312 as ALFONSO XI "el Justo" King of Castile and León. The cartulary of Tulle St Martin records the confirmation by "don Alfonso…rey de Castiella…" of donations made by his father on the advice of "la reyna dona maria nostra avuela et del Infant don Johan et del Infant don Pedro nuestros tios", dated 1318, subscribed by "D Johan fijo del Infant don Manuel mayordomo mayor del rey et adelantado del regno de Murcia, D Ferando fijo del Infant don Fernando, D Johan fijo del Infant don Johan, D Johan Alfonso de Haro senor de los Camos, D Ferrando fijo de don Diego, D Alfonso Tellez de Molina, D Ferrant Roys de Saldana, D Diego Gomes de Castaneda, D garci Ferrans de Villa mayor, D Lope de Mendoça, D Pedro Malrique, D Johan Remirez de Guzina, Don Beltran Yanos de Onate, D Roys Dios de Finojosa, D Johan de Castaneda, D Nuno Nunet de Aça, D Gonçalo fijo de don G Yans de Aguilar, D Roys Gonçals Maçanedo, D Per Anitians de Harana, D Lope Roys de Baeça, Gargilasso de la Vega merino mayor del rey en Castiella, El Infant don Felippe tio del rey et senor de Cabrera et de Ribera et partignero mayor de terra de Sant Yaguo…Don Garci Florens maestre de la cavalleria de la orden de Sant Iago, D Suer--- maestre de Alcantara, D Pedro Ferrans de Castro, D Ferrant--- Pons, D Gutierre, D Roy Gil de Villalobos, D Rodrigo de Villalobos, D Rodrig Alvarez de Asturias, D Diego Remirez, D Johan Arias de Asturias, Johan Alvarez Osoyro merino mayor de terra de Leon et de Asturias, Garci Rodrigues de Val carcel merino mayor de Gallisia, Johan Rodriguez de Roias algauzil mazor de casa del rey, Alfonso Joffre almirante mayor del rey en la mar, Diego Garci de Sotomayor notario mayor del regno de Leon, Ferrant Gomez notario mayor del rey en el regno de Toledo…".

The Chronicon Domini Joannis Emmanuelis records that “Dns Joannes filius Infantis Dni Emmanuelis et Dns Joannes filius Infantis Dni Joannis” renounced their tutorship over King Alfonso XI in Aug 1325.

He led the resistance to the invasion by Abu al-Hassan, Marinid Sultan of Morocco, defeating the Sultan at the battle of the river Salado 1340. His siege of Algeciras followed 1342-1344, supported by knights from all western Europe, which put an end to Marinid expansion. The Nobiliario of Pedro Conde de Barcelos records that King Alfonso XI died "Mancebo" and was buried "en Sevilla".

He died of the plague during the siege of Gibraltar. Ayala´s Crónica de Pedro I records that King Alfonso XI died at Gibraltar “por la pestilencia” 26 Mar 1350, and in a later passage his burial in Seville “en la capilla de los Reyes”, adding that his body was later transferred to “la Iglesia de Santa Maria de Cordoba, en la capilla dó yacia el Rey Don Ferrando su padre”. ¹