In the middle of the Lancet period was erected the grand façade in front of the Transitional western transept. It is not so much a façade, however, as an open portico or piazza. Several interesting engineering problems were involved. One was, how to keep up the three gigantic arches. If they had spread to north or south, the whole façade would have collapsed. To prevent their spreading, therefore, flanking towers were built to north and south; which in later days were weighted with spires. But there was a more serious danger. The two great isolated piers might be pushed outwards by the western thrust of the arches of the nave. These thrusts the builders stopped by building two towers; one over the westernmost bay of each aisle of the nave. The northern of these towers was soon after heightened; the other—the Bell Tower—remains low. The central gable had to be narrow, because it is the termination of the nave roof. The side-arches and side-gables had to be wide, to span the space from the nave to the sides of the Transitional façade behind. Though much narrower, however, the central gable rises as high as the lateral gables, being made to spring at a higher level; and it is made to look as important as the broad side-gables by being given the company of two powerful pinnacles. Thus the main features of this magnificent design are due to difficulties of planning and construction. The design is said to be drawn from Lincoln; it is more likely that it is an amplification of John de Cella’s lovely design for the west front of St. Albans. Abbot Acharius, who may well have commenced the work (1200-1210) had been Prior of St. Albans under John de Cella. Judging from the billet and nebula ornament on the gables, and from the arcading, in which semicircular arches and round-headed trefoils occur, the façade was designed in the very beginning of the thirteenth century. [Illustration: GABLE.] The west front of Peterborough has been severely criticised, especially by Mr. Pugin. To many it will ever seem the highest effort of English art, and to be at once the most original and most successful façade either in English or in Continental Gothic. Yet, magnificent and poetic as it is, we have not the full effect contemplated by the mediæval builders. They meant to have four towers, not three. The north-west tower was once crowned by a wooden spire; we may be sure that there would have been a spire also on the south-west tower. Add, too, in the background, the tall spire which was to be added to the central tower, and you have a group before which even Lichfield and Lincoln would pale into insignificance. But, even curtailed as it is, the design attains the sublime. When first its Titanic arches rose into the blue sky, its builders may well have repeated the psalmist’s words: “Lift up your heads, O ye gates; and be ye lift up, ye everlasting doors; and the King of Glory shall come in.” They had built a worthy portal to the House of the Almighty.