Procopius

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 gainsaid. Nor is there any reason it should be. Of what precise species this sea-monster was, is not mentioned. But as he destroyed ships, as well as for other reasons, he must have been a whale; and I am strongly inclined to think a sperm whale. And I will tell you why.

In the Propontis, as far as I can learn, none of that peculiar substance called brit is to be found, the aliment of the right whale. But I have every reason to believe that the food of the sperm whale—squid or cuttle-fish—lurks at the bottom of that sea, because large creatures, but by no means the largest of that sort, have been found at its surface. If, then, you properly put these statements together, and reason upon them a bit, you will clearly perceive that, according to all human reasoning, Procopius’s sea-monster, that for half a century stove the ships of a Roman Emperor, must in all probability have been a sperm whale.