Marriage, descendants and legacy
Leonor's first marriage was with Juan Téllez de Castilla, the second lord of Aguilar de Campoo and the second lord of Castañeda. He was the son of Tello de Castilla who was in turn, the illegitimate son of Alfonso XI of Castile and Eleanor de Guzmán. The couple had the following children:
Aldonza Téllez de Castilla y de la Vega (b. 1382 - d. 1449), who married Garci IV Fernández Manrique de Lara. The couple went on to become the first Counts of Castañeda. Their offspring went on to found the Marquesado de Aguilar de Campoo, the Ducado de Galisteo and the Condado de Osorno.
When Tello died on 14 August 1385 at the Battle of Aljubarrota, Leonor remarried in 1387 with Diego Hurtado de Mendoza, High Admiral of Castile, bringing with her dowry, the title over the town of Carrión de los Condes and a manor at Asturias de Santillana. The two had the following children:
García Lasso de la Vega, who according to his father's testamentary clauses had to change his name to Juan Hurtado de Mendoza.
Elvira Laso de Mendoza, married Gómez I Suárez de Figueroa. Their son was Lorenzo II Suárez de Figueroa, first Count of Feria.
Íñigo López de Mendoza, 1st Marquis of Santillana, founder of the powerful Dukedom of the Infantado and 1st Marquis of Santillana.
Gonzalo Ruiz de Mendoza, whose grandmother, Mencía de Cisneros]in her last will and testament of 1380 left him titles over Tierra de Campos and Vega with all its land and vassals.
Teresa de la Vega y Mendoza, married Álvaro Carrillo de Albornoz.
In August 1432, Leonor empowered her children Íñigo, Gonzalo y Elvira to draft her last will and testament, by which process, her daughter from her first marriage, Aldonza was disinherited.
After her death, all her domains went to the House of Mendoza through Íñigo López de Mendoza. In 1445 King, John II of Castile confirmed this action by granting the title of Marquis of Santillana, where after Santillana del Mar which became the center of the lordship of Torrelavega in Cantabria.
The Cantabrian surname "Lasso de la Vega" was passed on through this maternal line at later times throughout the years and is associated with various soldiers, poets, and golden age writers such as Garcilaso de la Vega, the soldier and poet, and Inca Garcilaso, the historian from the Viceroyalty of Peru.
