Res Gestae

Now at that same time the emperor Anastasius had three grandsons, namely, Pompeius, Probus, and Hypatius. Considering which one of them he should make his successor, he invited them to have luncheon with him one day, and after luncheon to take their midday siesta within the palace, where he had a couch prepared for each of them. Under the pillow on one couch he ordered the symbol of royalty to be put, and decided that whichever of them chose that couch for his nap, in him he ought to recognise the one to whom he should later turn over the rule. One of the grandsons threw himself down on one couch, but the other two, from brotherly affection, took their places together on another, and so it happened that none of them slept on the couch where the emblem of royalty had been placed.