Old Believers significant person Avvakum
Origins of reform
During the reign of Aleksei Mikhailovich (r. 1645–1676), the young tsar and his confessor, Stefan Vonifatiev, sponsored a group, mainly composed of non-monastic clergy and known as the Zealots of Piety. These included the archpriest Avvakum as a founder-member, as well as the future patriarch Nikon, who joined in 1649. Their original aim was to revitalise the parishes through effective preaching, the orderly celebration of the liturgy, and enforcement of the church's moral teachings. To ensure that the liturgy was celebrated correctly, its original and authentic form had to be established, but the way that Nikon did this caused disputes between him and other reformers.In 1646, Nikon first met Tsar Aleksei, who immediately appointed him archimandrite of the Novospassky monastery in Moscow. In 1649, Nikon was consecrated as the Metropolitan of Novgorod and, in 1652, he became Patriarch of Moscow. During his time in Novgorod, Nikon began to develop his view that the responsibility for the spiritual health of Russia lay with senior church leaders, not the tsar. When he became patriarch, he started to reorganise the church's administration so it was wholly under his own control.In 1649, a Greek delegation, headed by Patriarch Paisios of Jerusalem, arrived in Moscow and tried to convince the tsar and Nikon that current Greek liturgical practices were authentically Orthodox and that Russian usages that differed from them were local innovations. This led to a heated debate between the visiting Greeks and many Russian clerics who believed that, by accepting the decrees of the Council of Florence, the Greek patriarchate had compromised its authority and forfeited any right to dictate to Russia on liturgical matters. 
Tsar Aleksei, Nikon and some of the Zealots of Piety decided that the best way to revitalise the Russian church was to conform with the usages of the Greek church and accept the authority of the Patriarch of Constantinople.: 315–316