In the sixth Christian century lived Procopius, a Christian magistrate of Constantinople, in the days when Justinian was Emperor and Belisarius general. As many know, he wrote the history of his own times, a work every way of uncommon value. By the best authorities, he has always been considered a most trustworthy and unexaggerating historian, except in some one or two particulars, not at all affecting the matter presently to be mentioned.

Now, in this history of his, Procopius mentions that, during the term of his prefecture at Constantinople, a great sea-monster was captured in the neighboring Propontis, or Sea of Marmora, after having destroyed vessels at intervals in those waters for a period of more than fifty years.

A fact thus set down in substantial history cannot easily be