By Philip Pullella VATICAN CITY (Reuters) - Two giants of Roman Catholicism in the 20th century will become saints on Sunday at an unprecedented twin canonization that has aroused both joy and controversy in the 1.2 billion member Church. Pope John XXIII, who reigned from 1958 to 1963 and called the modernizing Second Vatican Council, and Pope John Paul II, who reigned for nearly 27 years before his death in 2005 and whose trips around the world made him the most visible pope in history, will be declared saints by Pope Francis. While John died half a century ago, critics say the canonization of John Paul - which sets a record for modern times of only nine years after his death - is too hasty. They also believe he was slow to grasp the seriousness of the sexual abuse crisis that emerged towards the end of his pontificate.