As one stands in the center of the church, gazing along its vaulting, it is easy to perceive that the axis is broken three times, and each divergence from the straight line conforms to one of the different stages of work. The deviation of the axis line once was called poetically _inclinato capite_ (_et inclinato capite, emisit spiritum_--St. John xix:30). It was thought to symbolize the inclining of Christ's head on the Cross. When M. Robert de Lasteyrie proved that a constructive miscalculation was the cause of the irregular line, the beautiful idea had to be renounced.[35] In each successive addition to a church it was difficult for the architect to start the new part exactly on the same axis as the old, since usually a temporary wall shut off the portion of the church already finished and in use. The slightest miscalculation at the start led to a very apparent deflection of alignment. Those churches which show irregular alignment are known to have been built in successive stages. A number of church choirs slant to the south, whereas were the figure on the crucifix taken as model they would deviate to the north. In churches without a transept, or, in other words, churches that lack the extended arms of the cross, is sometimes found a decided slant to the north. Moreover, the crucifix of that epoch represented a triumphant Christ with erect head, for the art of the XIII century was serene; the pathetic in religious iconography was a later development. No writer of the period mentions a symbolic interpretation of the deviated axis, not even Bishop Guillaume Durandus, in his noted _Rationale_, or _Signification of the Divine Offices_. There is, instead, a text of the XIV century which says that a certain architect was so chagrined at having built a tortuous axial line that he never returned to be paid by the cathedral chapter. Mr. Arthur Kingsley Porter thinks that the deviation of the axis was intentionally done, in order to overcome that tendency of perspective which lessens the apparent length of a church by foreshortening its far bays. By slanting the east end, the distant bays could be brought into view, and thus the edifice would seem longer. [Illustration: _St. Denis-en-France and Its Royal Mausoleums_]