Andrew of Constantinople (Andrew the Fool-for-Christ or Andrew, the Fool; Greek: Ἀνδρέας ὁ Σαλός;) is considered a saint by the Eastern Orthodox Church, and is revered as a Fool for Christ. Andrew, a Slav by birth, was a slave of Theognostus, who was serving as a bodyguard in Constantinople. Later, he decided to become a Fool for Christ, living out his goal with humility and patience. According to certain sources, Andrew had a vision of the Most Holy Theotokos in the Blachernae church of Constantinople, while the city was surrounded by enemy troops (by some sources, Muslim Arabs).