It take its name from the statues of saintly royalty which form part of its decoration , and is the oldest work in churrigueresque style in Mexico , taking 19 years to complete . At the bottom , from left to right , are six female royal saints : Saint Margaret of Scotland , Helena of Constantinople , Elisabeth of Hungary , Isabel of Portugal , Empress Cunegunda and Edith of Wilton . In the middle of the altar are six canonized kings , four of whom are : Hermenegild a Visigoth martyr , Henry II , Holy Roman Emperor , Edward the Confessor and Casimir of Poland . Above these four are Saints Louis of France and Ferdinand III of Castile . In between these kings an oil painting of the Adoration of the Magi by Juan Rodriguez Juarez show Jesus as the King of kings . The top portion feature a painting of the Assumption of Mary as celestial queen flanked by oval bas reliefs , one of Saint Joseph carrying the infant Jesus and the other of Saint Teresa of Ávila with a quill in her hand and the Holy Spirit above her , inspiring her to write . Above this are figures of Jesus and Mary among sculptures of angels crowned with an image of God , the Father .