Well-authenticated cases of the appearance of spirits of departed persons are mentioned in the earliest writings. Valerius Maximus relates in graphic words the experience of the poet Simonides, who was about to enter a vessel for the purpose of undertaking a long journey with some of his friends, when he discovered a dead body lying unburied on the sea-shore. Shocked by the impiety of the unknown man's friends, he delayed his departure to give to the corpse a decent funeral. During the following night, the spirit of this man appeared to him and advised him not to sail on the next day. He obeys the warning; his friends leave without him, and perish miserably in a great tempest. Deeply moved by his sad loss, but equally grateful for his own miraculous escape, he erected to the memory of his unknown friend a noble monument in verses, unmatched in beauty and pathos. Phlegon, also, the freedman of the Emperor Hadrian, has left us in his work, _De Mirabilibus_, one of the most touching instances of such ghost-seeing; it is the well-known story of Machates and Philimion, which Goethe reproduced in his "Bride of Corinth." Nor must we forget the numerous examples of visions in dreams, by which the Almighty chose to reveal His will to his beloved among the chosen people--a series of apparitions, which the Church has taken care to continue during the earlier ages, in almost unbroken succession from saint to saint. Pagans were converted by such revelations, martyrs were comforted, the wounded healed, and even an Emperor, Constantine, cured of leprosy, by the appearance of the two apostles, Peter and Paul.