Simón de Rojas (28 October 1552 – 29 September 1624) was a Spanish priest of the Trinitarian Order known as the "Apostle of the Ave Maria", for his devotion to the Blessed Virgin Mary.

Through profound theological studies, he came to understand even better the mission of Mary in cooperation with the Trinity for the salvation of the human race and the sanctification of the church.

For him, to be a slave of Mary meant belonging totally to her: "Totus tuus" in order to unite oneself more intimately to Christ and in him through the Spirit, to the Father.

When in 1611 she fell gravely ill following childbirth, becoming comatose, her husband King Philip III feared that she would be unable to receive the sacraments before dying.

Whilst working in the court Rojas had thousands of images of the Most Holy Virgin printed with the inscription: "Ave Maria", which he also sent abroad.

He had rosaries made with seventy-two blue beads on a white cord, symbols of the Assumption and the Immaculate Conception, and also a reminder that Mary, according to the belief of the time, lived to the age of 72 years.

Using his influence at court, he had the angelic greeting so dear to him, "Ave Maria", engraved in letters of gold on the facade of the royal palace in Madrid.

On 5 June 1622, he petitioned the Holy See for the approval of his liturgical text composed in honour of the Sweet Name of Mary, which later, Pope Innocent XI extended to the Catholic Church.