The Servian Wall was originally built from large blocks of Cappellaccio tuff (a volcanic rock made from ash and rock fragments that are ejected during a volcanic eruption) that was quarried from Alban Hills volcanic complex. This initial wall of Cappellaccio tuff was partially damaged and in need of restoration by the late 390s (either because of rapid disintegration or damage sustained after the Sack of Rome in 390 BC). These reparations were done using he superior Grotta Oscura tuff which had become available after the Romans had defeated Veii in the 390s. This tuff was quarried by the vanquished Veientines. In addition to the tuff blocks, some sections of the structure incorporated a deep fossa, or a ditch, in front of the wall, as a means to effectively heighten the wall. This second itteration of the wall containing Grotta Oscura tuff is dated by Livy to have been completed in 378 BC.