Pliny the Elder [1st century CE] (Natural History, Book 9, 5): Whales even penetrate into our seas. It is said that they are not seen in the Gulf of Cadiz before midwinter, but during the summer periods hide in a certain calm and spacious inlet, and take marvelous delight in breeding there: and that this is known to the killer whale [orca], a creature that is the enemy of the other species and the appearance of which can be represented by no other description except that of an enormous mass of flesh with savage teeth. The killer whales therefore burst into their retreats and bite and mangle their calves or the females that have calved or are still in calf, and charge and pierce them like warships ramming. The whales being sluggish in bending and slow in retreating, and burdened by their weight, and at this season also heavy with young or weakened by travail in giving birth, know only one refuge, to retreat to the deep sea and defend their safety by means of the ocean. Against this the killer whales use every effort to confront them and get in their way, and to slaughter them when cooped up in narrow straits or drive them into shallows and make them dash themselves upon rocks. To spectators these battles look as if the sea were raging against itself, as no winds are blowing in the gulf, but there are waves caused by the whales blowing and thrashing that are larger than those aroused by any whirlwinds. A killer whale was actually seen in the harbor of Ostia in battle with the Emperor Claudius; it had come at the time when he was engaged in completing the structure of the harbor, being tempted by the wreck of a cargo of hides imported from Gaul, and in glutting itself for a number of days had furrowed a hollow in the shallow bottom and had been banked up with sand by the waves so high that it was quite unable to turn round, and while it was pursuing its food which was driven forward to the shore by the waves its back projected far above the water like a capsized boat. Caesar gave orders for a barrier of nets to be stretched between the mouths of the harbor and setting out in person with the praetorian cohorts afforded a show to the Roman public, the soldiery hurling lances from the vessels against the creatures when they leapt up alongside, and we saw one of the boats sunk from being filled with water owing to a beast's snorting. - [Rackham translation]

Thomas of Cantimpré [circa 1200-1272 CE] (Liber de natura rerum, Marine monsters 6.38): The orca [orcha] is a sea monster, as Pliny says, whose image can be expressed by no other representation than that of an immense mass of flesh. They pursue whales, that is, cetaceans, with great hatred. With their teeth they savagely break into the secret places of cetaceans, or their calves, or whales, or even pregnant females, and tear them with their bites. These whales cannot bend, and are powerless to resist, and with their weight of honor and feeble fins only know how to take refuge in the deep sea and defend themselves with all the ocean. On the other hand, the orca, stubborn in their malice, rush to attack those who are fleeing, to confront them, and to constrain the unwary in narrow places, to force them into narrow straits and onto the rocks. Indeed, we believe that whales signify innocent and simple souls, both in good and evil alike inexperienced, who, when they have come to the company of good and the secret life, and have also begun to lead a life away from the world, and to increase the seed of good works conceived by the fear of God, at once that infernal gurgling monster the devil sets out to pursue them with different agitations of temptations, and now tries to force them into the straits of poverty, now into the vagaries of luxury, now into the stony danger which is the hardness of the heart. But they, being inexperienced in misery, unable to resist with frequent cleansing of the heart by prayers and fasting, or by confession, flee in broken despair to the great and fearful sea, and making void the first faith of chastity espoused to Christ, become free prey to the most cruel monster of ancient iniquity. - [Badke translation/paraphrase]