Sancia of Castile and Poland.

Princess of Castile, Queen Consort of Aragon and Countess consort of Barcelona. Was a founder of the Monastery of Sigena, is regarded as the founder of the Order of the Sisters of St John of Jerusalem, female branch of the Order of St John.

Daughter of the King of Castile, Alphonsus VII, and his second wife, Riquilda from Poland, was born on 1 September 1154.

The January 18, 1174, married in the Cathedral of Zaragoza with King Alphonsus "The Chaste" under the provisions of the Peace of Santa Perpetua de Sahagún. From this marriage were born: 

- Prince Peter the Catholic. Count of Barcelona and King of Aragon. 

- Princess Constance of Aragon. Queen consort of Hungary and Queen Consort of Germany. 

- Prince Alphonsus of Aragon. Count of Provence. 

- Princess Leonor of Aragon. Countess of Toulouse. 

- Princess Sancia of Aragon. Countess of Toulouse. 

- Prince Sancho of Aragon. Died in infancy. 

- Prince Ferdinand of Aragon. Abbot of the Abbey of Mont Aragon. 

- Princess Dulce of Aragon. Nun at the monastery of Santa Maria de Sigena.

After the death of her husband in Perpignan, in the year 1196, Sancia was relegated by her son Peter to a background position in political life. She left the court and retired to the Monastery of Santa Maria de Sigena, which she founded in 1188 and granted to the nuns of the Order of St John. She took the habit and lived as a nun until her death.

She took with her ​​daughter (the monastery), Constanza of Aragon, Queen of Hungary widow, who lived there between 1204 and 1208, when he went to Sicily to marry again. Sancia died shortly after, on 9 November 1208. She was buried before the high altar of the monastery. 

Like her husband, she was protective of troubadours as Guerau of Calanson and Peter Raimon.

Veneration.

What's founding in Sigena, the Monastery of Santa Maria de Sigena, is considered the founder of the women's branch of the Order of St. John of Jerusalem, and revered as God's servant within this Order. In many Sigena file documents speak of "Holy Queen Sancia, founder of this religion and convent."

In the Church of Our Lady of the Temple, in Zaragoza, a painting of Queen is preserved with an inscription that names "Holy Queen Sancia." Her cult, but had no impact outside the monasteries of the Order.