Alfonso IX of Leon and Galicia (August 15, 1171 – September 23 or 24, 1230), first cousin of Alfonso VIII of Castile and numbered next to him as being a junior member of the family, was the king of León from the death of his father Ferdinand II in 1188 until his own death. According to Ibn Khaldun, he is said to have been called the Baboso or Slobberer because he was subject to fits of rage during which he foamed at the mouth.

Alfonso was the only son of King Ferdinand II of León and Urraca of Portugal. Though he took a part in the work of the reconquest, this king is chiefly remembered for the difficulties into which his successive marriages led him with the Pope. He was first married in 1191 to his cousin Teresa of Portugal, who bore him two daughters, and a son who died young.

The marriage was declared null by the Pope; however, Alfonso paid no attention until he was presumably tired of his wife. His next step was to marry his second cousin, Berenguela of Castile, in 1197. For this act of contumacy, the king and the kingdom were placed under interdict.

The Pope was, however, compelled to modify his measures by the threat that, if the people could not obtain the services of religion, they would not support the clergy, and that heresy would spread. The king was left under interdict personally, but to that he showed himself indifferent, and he had the support of his clergy. Berenguela left him after the birth of five children, and the king then returned to Teresa, to whose daughters he left his kingdom in his will.

Alfonso's children by Teresa of Portugal were:

• Fernando (ca. 1192-August 1214), unmarried and without issue
• Blessed Sancha (ca. 1193-1270)
• Dulce, also called Aldonza (1194/ca. 1195-ca./aft. 1243), unmarried and without issue

His eldest daughter, Sancha, was engaged to her cousin King Henry I of Castile, but Henry died in 1217 before the marriage could be solemnized. Wanting to disinherit his eldest son, Fernando, King Alfonso invited John of Brienne to marry his daughter Sancha and thus inherit the Leonese throne. However, Queen Berenguela convinced John of Brienne to marry one of her daughters instead. Though she was the nominal heiress on her father's death in 1230, Sancha was easily set aside by Berenguela and Fernando. Sancha became a nun at Cozollos, where she died in 1270; she was later beatified. Her sister Dulce-Aldonza spent her life with their mother in Portugal.

Alfonso's children by Berenguela of Castile were:

• Leonor (1198/1199-October 31, 1210)
• King Fernando III the Saint (1200-1252)
• Alfonso, 4th Lord of Molina (1203-1272)
• Berenguela of Leon (1204-1237), married John of Brienne
• Constanza (May 1, 1200 or 1205-September 7, 1242), became a nun at Las Huelgas, Burgos, where she died

Alfonso also fathered many illegitimate children:

Alfonso's children by Aldonza Martínez da Silva (daughter of Martim Gomes da Silva & Urraca Rodrigues and subsequently wife with issue of Diego Froilaz, Conde de Cifuentes, had issue):

• Pedro Alfonso of León, 1st Lord of Tenorio (ca. 1196/ca. 1200-1226), Grand Master of Santiago, married N de Villarmayor, and had issue
• Alfonso Alfonso of León, died yong
• Fernando Alfonso of León, died young
• Rodrigo Alfonso of León (ca. 1210-ca. 1267), 1st Lord of Aliger and Governor of Zamora, married ca. 1240 to Inés Rodriguez de Cabrera (ca. 1200-), and had issue
• Teresa Alfonso of León (ca. 1210-), wife of Nuno Gonzalez de Lara, el Bueno, señor de Lara
• Aldonza Alonso of León (ca. 1212/ca. 1215-1266), wife of Diego Ramírez Froilaz, nephew of her stepfather, without issue, and of Pedro Ponce de Cabrera (ca. 1210-), and had issue, ancestors of the Ponce de León

Alfonso's child by Inés Iñíguez de Mendoza (ca. 1180-) (daughter of Lope Iñiguez de Mendoza, 1st Lord of Mendoza (ca. 1140-1189) and wife Teresa Ximénez de los Cameros (ca. 1150-)):

• Urraca Alfonso of León (ca. 1190/ca. 1197-), first wife ca. 1230 of Lopo III Díaz de Haro (1192-December 15, 1236), 11th Sovereign Lord of Viscaya, and had issue

Alfonso's child by Estefánia Pérez de Limia, daughter of Pedro Arias de Limia and wife, subsequently wife of Rodrigo Suárez, Merino mayor of Galicia, had issue):

• Fernando Alfonso of León (ca. 1211-), died young

Alfonso's children by Maua, of unknown origin:

• Fernando Alfonso of León (ca. 1215/1218/1220-Salamanca, 1278/1279), Archdean of Santiago, married to Aldara de Ulloa and had issue

Alfonso's children by Dona Teresa Gil de Soverosa (ca. 1170-) (daughter of Dom Gil Vasques de Soverosa & first wife Maria Aires de Fornelos):

• María Alfonso of León (ca. 1190/1200/1222-aft. 1252), married as his second wife Soeiro Aires de Valadares (ca. 1140-) and had issue and Álvaro Fernández de Lara (ca. 1200-) and had female issue, later mistress of her nephew Alfonso X of Castile
• Sancha Alfonso of León (1210/ca. 1210-1270), a Nun after divorcing without issue Simón Ruíz, Lord of Los Cameros
• Martín Alfonso of León (ca. 1210/ca. 1225-1274/ca. 1275)
• Urraca Alfonso of León (ca. 1210/1228-aft.1252, married twice, first to García Romeu of Tormos, without issue, then Pedro Núñez de Guzmán

Alfonso's other illegitimate child, mother unknown:

• Mayor Alfonso de León, married Rodrigo Gómez de Trava, without issue

Alfonso IX was the first King in Western Europe who summoned the citizens to the Parliament (León's Cortes of 1188). He also founded the University of Salamanca in 1208.

References

• Florez, Enrique. Reinas Catolicas, 1761
• Szabolcs de Vajay, "From Alfonso VIII to Alfonso X" in Studies in Genealogy and Family History in Tribute to Charles Evans on the Occasion of his Eightieth Birthday, 1989, pp. 366-417.