newly-conquered territory of Veii by granting its inhabitants citizenship without the right to vote and by a strengthening of the alliance with Caere, which had helped Rome during the Gallic sack. After the initial setback and attacks, Rome resumed its expansionism of the late 5th and early 4th centuries. Rome rebuilds its city walls A few years after the sack, Rome began to build new city walls using ashlar masonry from a quarry in the territory of Veii. It was a huge undertaking as the wall was 11 km (7 mi) long. The original wall had been built in carpaccio tuff, the local stone, which was of rather poor quality because it is a quite friable stone. The wall was rebuilt with a type of yellow tuff, named Grotta Oscura (after its main quarry), which was of much better quality, in the territory of Veii. Thus, the acquisition of Veii provided Rome with better masonry for construction. However, the new rock was harder and thus more difficult to work. Fear of Gauls The Gallic sack led to a long-lasting and profound fear of the Gauls in Rome. In 350 and 349 BC, unspecified Gauls attacked Latium. They were probably marauding raids. On the second occasion, Marcus Valerius Corvus was said to have fought a duel with a Gallic champion. Polybius said that Rome made a peace with the Gauls, who did not return for 30 years. Despite Rome defeating the Senones in the Battle of Sentinum (295) during the Third Samnite War (298-290), popular fear of Gauls persisted. In 228, 216, and 114 fears of Gallic attacks led to the Romans performing human sacrifices by burying alive a pair of Gauls and a pair of Greeks even though human sacrifice was not a Roman custom. Presumably, it was done to avert the danger of another Gallic disaster. Legend about Brennus The Historia Regum Britanniae, a medieval work of fiction written c. 1136 by Geoffrey of Monmouth on the legendary kings of Britain, depicts Brennus as leading both Britons and Gauls. He besieges Rome for three days until his brother comes to aid in the invasion. The Romans defend the city for many days and are successful in repelling the invaders. Finally, the two consuls don armour and join the men defending the city. They push the invaders back, but Belinus can reform the lines and stop the attacks. Brennus and