TESSERÆ, or TICKETS, were written testimonials to character, much in use in the primitive church. By means of letters, and of brethren who travelled about, even the most remote churches of the Roman empire were connected together. When a Christian arrived in a strange town, he first inquired for the church; and he was here received as a brother, and provided with every thing needful for his spiritual or corporeal sustenance. But since deceivers, spies with evil intentions, and false teachers abused the confidence and the kindness of Christians, some measure of precaution became necessary, in order to avert the many injuries which might result from this conduct. An arrangement was therefore introduced, that only such travelling Christians should be received as brethren into churches where they were strangers, as could produce a testimonial from the bishop of the church from which they came. They called these church letters, which were a kind of _tesseræ hospitales_, [tickets of hospitality,] by which the Christians of all quarters of the world were brought into connection, _epistolæ_, or _literæ_ _formatæ_, [formal letters,] γράμματα τετυπώμενα, because, in order to avoid forgery, they were made after a certain _schema_, (τυπὸς, _forma_,) or else, _epistolæ communicatoriæ_, [epistles of fellowship,] γράμματα κοινωνικά, because they contained a proof that those who brought them were in the communion of the church, as well as that the bishops, who mutually sent and received such letters, were in connection together by the communion of the church; and afterward these church letters, _epistolæ clericæ_, were divided into different classes, according to the difference of their purposes.