After Arnolfo died in 1302, work on the cathedral slowed for almost 50 years. When the relics of Saint Zenobius were discovered in 1330 in Santa Reparata, the project gained a new impetus. In 1331, the Arte della Lana, the guild of wool merchants, took over patronage for the construction of the cathedral and in 1334 appointed Giotto to oversee the work. Assisted by Andrea Pisano, Giotto continued di Cambio's design. His major accomplishment was the building of the campanile. When Giotto died on 8 January 1337, Andrea Pisano continued the building until work was halted due to the Black Death in 1348.