Originally written in Spanish by Saint Teresa of Ávila in 1577, "El Castillo Interior" or "The Interior Castle" is a guide for spiritual development through service and prayer. Saint Teresa began writing "The Interior Castle" on June 2, 1577, Trinity Sunday, and completed it on the eve of St. Andrew's Day, November 29, 1577. Between these two dates her writing was interrupted for five months however, thus the actual total time she spent writing the work was approximately twenty-eight days. This work in conjunction with and "The Way of Perfection" can be seen as practical guides for "seekers" who want to really understand prayer as mystical union with God. "The Interior Castle" is divided into seven mansions, each level describing a step to get closer to God. A classic work of Christian mysticism which is an integral part of Spanish Renaissance literature, "The Interior Castle" is considered Saint Teresa of Ávila's seminal work.