Why is mathematics important to theology?

According to Roger Bacon in his Opus Majus there are seven reasons.  One of them has to do with geography.  Basically, his theory is that we cannot rightly understand the scriptures if we do not understand the geographical situation of its histories.  Because, if we cannot understand that, we cannot understand the literal sense of the scripture, and if we cannot grasp the literal, how can we hope to understand any spiritual meaning? 

This was one example offered:
" We note that the Jordan flows down from north to south to the east of Jerusalem, which lies to the west, a little way from the Great [Mediterranean] Sea. Between these two, on this side of Jordan, is Jericho, a city surrounded by its plain. Next comes Mount Olivet, then the Valley of Josaphat, and after it Jerusalem. Now the saints tell us that the world is represented in their method of interpretation by Jordan, both symbolically and because of the river's characteristics. For one thing, it flows into the Dead Sea, a symbol of the Inferno; there are also many other reasons. Jericho, in the view of the saints, symbolizes the flesh. Mount Olivet signifies the loftiness of the spiritual life, because of its own loftiness, and the sweetness of devotion, as sweet as its oil. The Valley of Josaphat signifies lowliness through the meaning of valley, "a low place," and true humility in the presence of majesty, (186) since the translation of the name Josaphat is "in the sight of the Lord." Jerusalem itself means "vision of peace"; in its moral interpretation it points to the holy soul which possesses peace of heart. Allegorically it signifies the Church Militant; analogically, the Church Triumphant.
We all hope to pass with peace in our hearts from the beginning of our life (the dawn of our physical birth and the sunrise of reason's theory and practice) to its end, the sunset of old age; this is our hope expressed in moral terms. We all hope to be true and faithful members of the Church, beneath whose shade we may rest, untroubled by the malign assaults of our enemy; this is the same hope expressed as allegory. We hope that in this life our thoughts may be turned [by analogy] to the heavenly Jerusalem, and that at our death we may pass to that heavenly city, there to dwell in the beauty of peace, in the tents of faith, in rest and in fullness. Whoever hopes for all this must first leave Jordan-this world-behind, either by reducing it to his control, like the saints who live in the world, or abandon it completely, as the monastics do. This is the first stage of progress to a spiritual life, a stage easier than the others.
Having achieved this, he must next do battle with the flesh, something not as easy to overcome as the world, being very close to us and never abandoning its subject.[isn't that the truth!] He must not, therefore, charge it by brute force and destroy it, but must bridle its arrogance slowly and tactfully. This is why it is figured by Jericho and the plain around it; one must advance in penitence along the level road, thus justifying the reasonable obedience of his flesh. For if he foolishly overwhelms his flesh by violence, his spirit can never attain the greater heights. In acting patiently he will be unlike most people who have been turned to penitence, who for a year or two humble their own bodies, but thereafter are good for nothing, unable to benefit themselves or anyone else.
But after a man has put down the world under his feet and has overcome the flesh in the way he should, then-and not until then-he is ready to rise up to the heights of spiritual life and the sweetness of true devotion. From then on he will be able to climb up to Mount Olivet and gain the pinnacle of human perfection and immerse himself in the delight of prayer and contemplation of God. But even when he has trained himself by the ascent from all sides of that height, he must still cross the valley of Josaphat-that is, he must finish the course of his life in complete humility and make himself poor and humble of spirit in the eyes of God, not merely his own or those of his fellow men. For many look humble to themselves and to other men, but in the presence (187) of God and his angels are puffed up with arrogance.[never thought of that]
When at last he has ended his whole life in perfect lowliness, then he has entered Jerusalem, in all three senses of the word. He will possess peace in his heart, the peace which follows perfection of the life of the spirit. "To the ungodly there is no peace," says the Lord. But the saints possess the peace of God, which transcends the senses of mankind. Free from all troubles, he will rest in the peace of the Church Militant-the peace unknown to the faithless and sinful, who drag on in the state of damnation, plagued by the Devil and driven from one sin to another, punished for one, then tormented for another. Even in this life he must play his part, as it is said, by sure and certain hope and by revelation, in that blessed vision of the peace of Jerusalem that is above, which by the grace of God he will win after his death."
I never thought of geography that way . . .