Mirabilia or terribilia?
Sea monsters as symbols in Medieval exegesis
Although Medieval biologists reported about many sea animals in books called De monstris marinis, they regarded them not only as wondrous or strange (mirabilia), but also as frightening or terrible (terribilia). The same ambivalency of the word monstrum is detectable in allegorical interpretations by Medieval exegetes and moralizers who frequently interpreted the same symbol in contradictory terms.
In its positive aspect the sea symbolizes baptism, the Gospel or the Church, fish symbolize believers caught in the nets of the fishermen-apostels in order to reach eternal salvation through faith. On the other hand, the sea represents this world inhabited by small fish as well as huge monsters. Huge sea animals are the mighty ones in this world, while smaller fish are the common people of any age, status, language or sex. As some sea fish are harmless and have a simple diet and others are greedy and devour other sea animals, so it is in this world: some people are like the greedy fish, and though they are washed by the “sea water”, i.e. they have been baptized and received the Christian faith, they live as sinners and tyrants. The sea fish in all their variety of looks and behaviour represent the wanderers in this world who strive to attain immortality and whose life is constantly shaped by their desires, aspirations, virtues and weaknesses, with all their various activites and positive and negative attitudes to others. There is much admirable in their conduct and so it is not surprising that Medieval moralizers compare some sea animals with Christ, the apostels and martyrs, who sacrificed their life for the salvation of mankind, but also scholars, monks and priests who have become the servants of God and neighbours. Terrible looks and spiteful behaviour of other sea fish recall the worst human qualities: godlessness, cruelty, arrogance, profligacy, greed for possessions and power, and desire to denigrate and harm others.
But the contemporary world is not afflicted by these unworthy Christians only. As the sea is stirred by whirls and winds, the world is also full of the waves of temptation, troubled by the storms of suffering and the winds of unrest. The ships that sail on this restless sea trying to reach the shore represent the Church and the faithful who sail on the wooden craft, the symbol of the Cross, for the haven of the eternal bliss. Their effort to reach the haven is frustrated by terrible monsters, the most horrible of all being the spiteful killing dragon, the devil, who lives in the most profound depths of the sea. This depth is no longer a place in the world. Rather, in the eyes of the Medieval exegetes the devil turns the sea into a symbol of the bottomless depth of hell down to which he constantly tries to drag the sailors by means of sin.