Piero's most important work was the fresco cycle he painted in the apse of San Francesco in Arezzo which depicts the legend of the True Cross in ten scenes. All of these frescoes, including The Battle between Heraclius and Chosroes, contain many of the stylistic and scientific developments of painting that occurred during the Early Renaissance: a love for monumental compositions, the use of perspective, proportions, light, and colour to create realism in both figures and landscape. Typical of the Early Renaissance, the expressions of the figures are calm and detached even as they engage in battle.
