From the death of King Sancho IV of Castile, his brother John (https://en.wikipedia.org/wiki/John_of_Castile,_Lord_of_Valencia_de_Campos) was declared King of Leon from Seville and Galicia in opposition to Sancho's son, Ferdinand IV.
IOTL, after 4 or 5 years, he reconciled with his nephew before dying in 1319. I'm not sure if he had any ambitions to overthrow his nephew, but what if he did and had?
IOTL, after 4 or 5 years, he reconciled with his nephew before dying in 1319. I'm not sure if he had any ambitions to overthrow his nephew, but what if he did and had?