John of Ruusbroec – Wikipedia
The Blessed John van Ruysbroeck (Dutch: Jan van Ruusbroec, pronounced [ˈjɑn vɑn ˈryzbruk]; 1293 or 1294 – 2 December 1381) was one of the Flemish mystics. Some of his main literary works include The Kingdom of the Divine Lovers, The Twelve Beguines, The Spiritual Espousals, A Mirror of Eternal Blessedness, The Little Book of Enlightenment, and The Sparkling Stone. Some of his letters also survive, as well as several short sayings (recorded by some of his disciples, such as Jan van Leeuwen). He wrote in the Dutch vernacular, the language of the common people of the Low Countries, rather than in Latin, the language of the Church liturgy and official texts, in order to reach a wider audience.