Sancho's younger sister Berengaria was married to Richard I of England in 1191 on the island of Cyprus on the way to the Holy Land for the Third Crusade.

The French took advantage of Richard's captivity in Germany and captured certain key fortresses of the Plantagenet dominions including Loches.

But others suspect they represented the Basques' star-like Sun of Death seen on their Hilarri (Basques' Stelae) or houses traditionally for protection, and perhaps painted on their shields too with the same religious purpose, meaning of Life or Death, or the new Imagery used for Jesus or Christianity as for others were the Christi Anagram or plain Cross on the shield.

As the result of prolonged and painful illness, starting with a varicose ulcer on his right leg and ashamed of it and his consequent obesity, Sancho went into retirement at Tudela at some point, when his youngest sister Blanche came from Champagne and took administration of the kingdom until she died in 1229.

When he died in his castle at Tudela, probably of complications related to the varicose ulcer in his leg, his only nephew and Blanche's son Theobald IV of Champagne was recognized as his successor.

[4] The cultural contacts with the Muslim Kingdoms that he visited and battled with, his friendship with his brother-in-law King Richard, and his sister Blanche's court of Troyes, at the time the most refined in Europe, must have left an important influence on the King's personal intellect, bringing to him an advantageous outlook from the one well set already by their father at his youth, full however with peccadilloes and other impetuous extravaganza.

Sancho left the kingdom with a wealthy treasury and improved communications was in his day one of the most advanced in human rights, and its Jewish community enjoyed the best standing in Christian Europe, which after all had been the work and result of the Jimenez royal house for centuries.

His remains have since been exhumed for study and examined by the physician Luis del Campo, also the king's biographer, who measured him at 2.20 metres tall (7'3"), probably the basis for his "strength" epitaph.