About 1115 was begun the present collegiate as a Romanesque edifice; the north arm of the easternmost transept and the side wall between it and the larger transept are pre-Gothic. St. Quentin is an exception, in France, in possessing two transepts. When in 1257 St. Louis came to St. Quentin for the removal of the martyrs' relics to the new crypt, the Gothic choir was completed. Three of the small chambers in the XIII-century crypt are of Carolingian origin, and vestiges of Carolingian work remain in the west tower, placed directly before the church, and serving as a kind of vestibule to it. Till the present nave was extended to meet that ancient belfry, it stood isolated.
Fissures showed in the new constructions and much time was wasted in consolidations. Only as the XIV century opened was the big transept between choir and nave begun; it was made twenty feet wider than the transept between apse curve and choir. The tracery in the rose windows of both cross inclosures is most artistic. The nave continued building all through the XIV century. It repeated the shafts which, in the choir, had been later additions needed for consolidation. Only by 1470 was St. Quentin's nave completed by joining it to the ancient west tower. Three different campaigns of work built this church, and three breaks in its axial line are distinctly visible. Toward its repairs the good king Charles V contributed, and Louis XI bore the expense of remaking the small transept.
To Villard de Honnecourt is attributed the plan of St. Quentin, since there are details in his sketchbook--the thirty-three parchment leaves now a treasure of the National Library at Paris--to substantiate the claim. His annotations are in the Picard dialect. St. Quentin's ordinance followed that of Rheims Cathedral sketched by Villard. The planting of columns between axis chapel and ambulatory--a Champagne feature--is the kind of charming novelty which would have appealed to the eager traveler who, at Kassovie, made a church for the king of Hungary wherein he repeated the unique fan-spreading eastern end of St. Yved at Braine.
Thus he opened his precious book: "Villard de Honnecourt salutes you, and he begs all those who work at different classes of studies contained in these pages, to pray for his soul and remember him, for in this book can be found great help in teaching oneself fundamental principles of masonry and church carpentry."