All the liturgical commentators are agreed that the high altar must be placed at the eastern end, so that the worshippers, as they pray, may turn their eyes towards the cradle of the Faith; and this rule was held absolute, and so well approved by God that He confirmed it by a miracle.

The Bollandists in fact have a legend that Dunstan, Archbishop of Canterbury, seeing a church that had been built on another axis, made it turn to the East by a push with his shoulder, thus placing it in its right position.
"The church has generally three doors, in honour of the Holy Trinity; and the portal in the middle, called the Royal Porch, is divided by a pier and a pillar surmounted by a statue of Our Lord, who says of Himself in the Gospel, 'I am the door,' or of the Virgin, if the Church is consecrated to Her, or even of the patron Saint in whose name it is dedicated.

The door, thus divided, typifies the two roads which man is free to follow.

Indeed, in most cathedrals this symbol is emphasized by a representation of the Last Judgment placed above the entrance.
"This is the case in Paris, at Amiens, and at Bourges.

At Chartres, on the contrary, the Judgment of Souls is relegated, as at Reims, to the tympanum of the northern porch; but here it is to be seen in the rose-window over the western portal, in contradiction to the system usual in the Middle Ages of treating in the windows above the doors the subject carved in the porch; thus presenting on the same side a repetition of the same symbols, in glass as seen from within, and in stone without." "Good; but how then can you account, by the ternary rule so universally adopted, for that marvellous cathedral at Bourges, where, instead of three porches and three aisles, we find five ?" "Nothing can be simpler--we cannot account for it.