Christianity consists of different denominations (Greek Orthodox, Catholic, High Anglican). However, all Christian denominations share a common gospel value -the belief in Jesus, this is what brings various Christian churches together and this unity is known as ecumenism. Pope John XXIII reintroduced ecumenism and it was very successful, due to the effects it had on Christianity and its adherents.
Pope John XXIII made some changes within the Catholic Church. Pope John XXIII removed the three ills of the church (Triumphalism- belief that the Catholic Church alone held the truth, Clericalism- The emphasis on clergy and exclusion of laity and Jurisdiction- legalism to the detriment of people), This was a very effective way of getting the laity involved in the church (esp. the youth) as the laity become active within the Church, lay people could take part in some sacred rituals of the church (alter server) and help distribute the Holy Eucharist. As for clergy, their job is to guide, nurture, and guard the laity, the clergy “is the shepherd of the flock”. As a result of these three Ills being removed, Christian adherents saw Catholicism as a denomination open to dialogue and a lot more welcoming than it was before.
The Liturgy had emphasis on sacredness of liturgy as a means of salvation. It had care in keeping liturgy uniform and Latin was used throughout world masses with priests performing and laity observing. During Post Vatican it changed, the liturgy was known as a celebration, vernacular languages were introduced to masses and everyone would participate, allowing diverse ministries. Hence, the