The four types of seeds that God’s messenger, Grace gives Piers Plowman to plant represent the four cardinal virtues of prudence, temperance, fortitude, and justice. For these virtues to be grown successfully, Piers must use the four oxen (the four Gospels), the four horses (the four Fathers of the Western Church), and two harrows (the Old Testament and the New Testament). Once the four seeds grow into grain, Piers is to store them in the barn called Unity, where the Christian community resides, suggesting that the four cardinal virtues must be carefully cultivated and are nourishment for the Church.
The timeline below shows where the symbol Four types of seeds appears in Piers Plowman. The colored dots and icons indicate which themes are associated with that appearance.