Aristides the Athenian (also known as Saint Aristides or Marcianus Aristides; Greek: Ἀριστείδης Μαρκιανός) was a Greek Christian author who is primarily known for authoring the Apology of Aristides in the 2nd century Revered as a saint, his feast day is August 31 in the Catholic Church and September 13 in the Eastern Orthodox Church.
General info from Wikipedia.org