(Photo: Reuters / Gareth Fuller / Pool)The new Archbishop of Canterbury Justin Welby gestures after being enthroned during a ceremony at Canterbury Cathedral, in Canterbury, southern England March 21, 2013.

The Archbishop of Canterbury, Rev Justin Welby, was enthroned Thursday for the first time by a woman as the senior cleric of the Church of England and the spiritual leader of the 80-million strong worldwide Anglican Communion.

"There is every possible reason for optimism about the future of Christian faith in our world and in this country," said Archbishop Justin in his first sermon.

"The present challenges of environment and economy, of human development and global poverty, can only be faced with extraordinary Christ-liberated courage."

The Archbishop added, "Courage is released in a society that is under the authority of God, so that we may become the fully human community of which we all dream."

Representives of other Christian traditions such as the Roman Catholic Church, Orthodox churches, other denominations and faiths including Hindus, Jews, Muslims and Sikhs were in the 2,000 strong congregation for the enthronement of the 105th Arcbhbishop of Canterbury.

Ecumenical representatives included Rev. Olav Fyske Tveit, General Secretary of the World Council of Chuches; Archbishop Gregorios of Thyatiera and Great Britain; the Moderator of the Free Churches Group, Rev. Michael Heaney; and Metropolitan Hilarion, Hierarch of the Russian Orthodox Church Outside Russia. Cardinal Kurt Koch, President of the Pontifical Council for Promoting Christian Unity, came from the Vatican.

First, the Archbishop was installed on the Diocesan throne as the Bishop of the see of Canterbury, the oldest diocese in the English church.

He was then installed on the chair of St. Augustine as Primate of All England – the "first bishop" in the country.

The legal confirmation of the 57-year-old on March 4 had ended his role as Bishop of Durham and took place in a legal ceremony at London's St. Paul's Cathedral

His second enthronement on Thursday is the one seen as representing the Archbishop's inauguration as the spiritual leader of the worldwide Anglican Communion.

The Venerable Sheila Watson firstly installed the archbishop on the diocesan throne in the cathedral. Then he was sworn in as the Archbishop of Canterbury by the Dean of Canterbury, Rev. Robert Willis, on the marble chair of St. Augustine.

Welby along with most of the clergy in the Church of England support the ordination of feamle bishops, but they do not have enough backing from church members yet.

At 3 p.m. (GMT) on Thursday, Welby waited outside the cathedral's west door where the Dean of Canterbury Cathedral, Robert Willis, was inside reading out a letter from British monarch Queen Elizabeth II, Supreme Governor of the Church of England.

The letter authorized the dean and cathedral community representatives to go to the church's west door to greet the Archbishop.

The Archbishop then struck the door three times with his pastoral staff, and the dean opened the door to greet him.

He was greeted by 17-year-old Evangeline Kanagasooriam, who said, "We greet you in the name of Christ. Who are you and why do you request entry?"

"I am Justin, a servant of Jesus Christ, and I come as one seeking the grace of God, to travel with you in his service together," said the Archbishop.

The Archbishop added, "I am sent as Archbishop to serve you, to proclaim the love of Christ and with you to worship and love him with heart and soul, mind and strength."

The Archbishop was led up to the nave altar, where the Archbishop of York, John Sentamu, asked him to swear an oath of faithfulness to the statutes of the Church of England and an oath of faithfulness to the Queen of England.

The congregation applaued him, dancing and drumming following. The dancers were from London group who used melodies from Ghana. The dancers led the Archbishop to the pulpit, where he proclaimed the Gospel, a passage from Matthew 14, the account of Jesus walking on water.