or Sincellus, an ancient officer in the family of the patriarchs and other prelates of the eastern church. The word, in the corrupt Greek, εὐρεῖλλος, signifies a person who lies in the chamber with another; a chamber-fellow, or chum. The syncellus was an ecclesiastic, who lived with the patriarch of Constantinople, to be a witness of his conduct; whence it is that the syncellus was also called the patriarch's eye, because his business was to observe and watch. The other prelates had also their syncelli, who were clerks living in the house with them, and even lying in the same chamber, to be witnesses of the purity of their manners. The office afterwards degenerated into a mere dignity; and there were made syncelli of churches. At last, it became a title of honour, and was bestowed by the emperor on the prelates themselves; whom they called pontifical syncelli, and syncelli Augustales.