St. Gertrude the Great was born on Epiphany, 1256 in what is now Germany. She was raised in a monastery, where she received a thorough education. At 25, she began to have visions. She devoted herself to prayer and her writings focused more on spiritual than academic matter.
She wrote a large portion of A Herald of Divine Love (other parts written by her peers). She also wrote her own Spiritual Exercises. It included prayers for various liturgies and feast days throughout the year. St. Francis de Sales used her prayers, and they have been popular throughout Europe for centuries.
She is one of the earliest known devotees to the Sacred Heart of Jesus. She had a vision of Christ’s heart, pouring forth like a redemptive fountain from the wound in his side.
One of her most popular prayers is for those in purgatory. She is one of few saints (and to my knowledge the only women) with the title “Great.” She died in 1302. Her feast day is November 16.