St. Gertrude the Great, or St. Gertrude of Helfta, was born on January 6, 1256, in Germany. She eventually chose to follow the Lord by pursuing a vocation as a Benedictine Nun. Her deep relationship with the Lord in prayer led to her being hailed as a mystic. She was also regarded as a great theologian.
Although little is known about Gertrude's childhood, it is widely accepted that at just four-years-old, she was enrolled in the Cistercian monastery school of Helfta in Saxony, under the governance of Abbess Gertrude of Hackerborn.
The Cistercian movement was an effort to bring the Benedictine religious community back to a stricter and more faithful adherence to the original "Rule" or way of life encouraged by St Benedict. Some sources speculate that Gertrude's parents offered their child as an oblate, a layperson especially dedicated to God or to God's service, while others believe she may have entered the monastery school as an orphan.
St. Mechtilde, the younger sister of the Abbess Gertrude, took care of young Gertrude. Gertrude and Mechtilde had a strong bond that only grew deeper with time, allowing Mechtilde to have a great influence on Gertrude.
Gertrude, known for being charming and able to win people over, entered the Benedictine Order at Helfta and became a nun. She devoted herself to her studies and received an education in many different subjects. Gertrude was both fluent in Latin and very familiar with scripture and works from the Fathers of the Church, including Augustine.
In 1281, 25-year-old Gertrude experienced her first series of visions that would continue until the day she passed away. Her visions altered her life and she saw this moment as her new birth. Her priorities turned away from secular teachings and focused more on studying Scripture and theology. Her life became full with this awakening and she was an enthusiastic student, writing for the spiritual benefit of others.
Gertrude once had a vision on the feast of John the Evangelist, described in Gertrude's writings. As she rested her head near Jesus' wound on his side, she could hear the beating of his heart. She asked St. John if he, too, felt the beating of Jesus' Divine Heart on the night of the Last Supper. He told her he was saving this revelation for a time when the world needed it to rekindle its love.
She went on to become one of the great mystics of the 13th century. Along with St. Mechtilde, she practiced what is known as "nuptial mysticism," seeing herself as the bride of Christ. She embraced charity for both rich and poor, she was a simple woman with a deep solidarity with those not yet ready for the beatific vision, who are still being purified in the state of repose known as purgatory.
Source - http://www.catholic.org