[78] There is a similar stairway in the church of S. Agnese fuori le mura, at Rome, which though originally said to have been founded by Constantine, is not of Greek form, but preserves a perfect Basilican plan. It was enlarged by Pope Symmachus in the fifth century, and he, it is known, employed Italian artists. The spiral stairway (_cochlea_) is also mentioned at Hexham in England. [79] _L' Architettura in Italia_, ch. iii. p. 143. [80] Anastasii, _Bibliothecarii Vitæ Romanorum Pontificum_--in Muratori, _Sculptores Rerum Italicum_, tom. iii. [81] S. Prassede in Rome, which was standing in the time of Pope Symmachus, when in 477 he held a synod there, has the same peculiarity. The elongated piers are here placed between every two columns, and are transverse, _i.e._ the greater width across the church. Before this time the roofs were always formed of gable-shaped frames of wood, erected on beams resting on the side walls, but Ricci sees in this the first advance towards the arched roof. We may see the next step in the old Lombard church at Tournus in France, where a succession of arches are thrown across the nave from the piers. [82] The tower, which is in a later Lombard style, was rebuilt two centuries later. CHAPTER VI IN THE TROUBLOUS TIMES After the Carlovingian dynasty had withdrawn from Italy, the country had two or three centuries of troublous times, in which very few people thought of church-building, and if the Comacine Masters found work in their own land, it was more the building of castles and strongholds in their most solid _opera gallica_, than the sculpturing of saints or the rearing of gorgeous basilicæ. After the Carlovingians came the House of Berengarius, which held the Italian throne from 888 to the intervention of Otho I. of Germany in 951. During this time there was always a military fermentation going on; Duke Guido of Spoleto fighting Berengarius; Arnolph and his son Sventebald fighting Guido; the Hungarians overrunning and sacking Italy on the north, where there were battles at Brenta, Garigliano, Firenzuola, and bloodshed generally till the murder of Berengarius. Nor were things more peaceful in the south. Between A.D. 924 and 950 the Saracens invaded Sicily, and having established themselves there, assaulted Rome, and marched on towards the Alps. In Central Italy the Dukes of Burgundy, Provence, and Bavaria were found contesting with Lothaire for the succession. At length, in 951, Otho came down from Germany and scattered them all, restoring comparative peace for a time, though an arbitrary one; but it did not last long.