The "Chronicon Paschale" or "Easter Chronicle" is an important part of the Byzantine chronographic tradition of the late antique period. It was composed at Saint Sophia in 630, probably under the patronage of the Patriarch Sergius. It provides evidence of the riots, plots and massacres of Phocas' reign, the financial difficulties of the time, the Avar siege of Constantinople in 626, and the triumph over the Persians under Heraclius in 628.