The outbreak of Schism in 1378 introduced a shift in searching for a new source of authority which could legitimise the church reform. Since the early 1390s, the conciliar tradition preferring the canon law as the leading authority for determining the Schism has been constituted and supported among French or German theologians. Nevertheless, in the late 1370s, John Wyclif developed another solution for church reform favouring God’s law and the ideal of a top-down reformation led by righteous civil lords, which Jan Hus and his followers further adopted within the early 15th Century. Conciliarism and the English model for church reform proposed by Wyclif competed in politics after 1409. Recently, new sources treating the clashes over authority issues in the Middle Ages were published, which shed new light on the problem.