Saint Gildas of Brittany was a sixth-century monk and writer, known for his role in the early Christian church in Brittany. He is often credited with founding several monasteries and spreading Christianity in the region. Gildas is also recognized for his writings, particularly "De Excidio et Conquestu Britanniae," which discusses the history and moral decline of Britain. Gildas is venerated as a saint in both the Catholic Church and the Eastern Orthodox Church. His feast day is celebrated on January 29. He is often depicted in art with a book or scroll, symbolizing his contributions to Christian literature and education.