XVI.
Abu Ali Yahya, the vizier of Harun-ar-Rashid, was the son of Khalid, and the grandson of Barmek. Yahya was highly distinguished for wisdom, nobleness of mind, and elegance of language. One of his sayings was: 'Three things indicate the degree of intelligence possessed by him who does them: the bestowing of gifts, the drawing up of letters, and the acting as ambassador.' He used to say to his sons: 'Write down the best things which you hear; learn by heart the best things which you write down; and in speaking utter the best things which you have learned by heart.'