The Archbishop of Canterbury is the chief bishop and principal leader of the Church of England, the symbolic head of the worldwide Anglican Communion and the diocesan bishop of the Diocese of Canterbury, the see that churches must be in communion with in order to be a part of the Anglican Communion.
From the time of St Augustine until the 16th century, the Archbishops of Canterbury were in full communion with the See of Rome and thus received the pallium. During the English Reformation the church broke away from the authority of the Pope and the Roman Catholic Church, at first temporarily and later more permanently. Since then they have been outside of the succession of the Roman Catholic Church's hierarchy and have led the independent national church (though ironically still retain the papal pallium on their coat of arms).
In the Middle Ages there was considerable variation in the nomination of the Archbishop of Canterbury and other bishops. At various times the choice was made by the canons of Canterbury Cathedral, the King of England, or the Pope. Since the English Reformation, the Church of England has been more explicitly a state church and the choice is legally that of the British crown; today it is made in the name of the Sovereign by the Prime Minister, from a shortlist of two selected by an ad hoc committee called the Crown Nominations Commission.
Today the archbishop fills four main roles:
In respect of the last two of these functions, he has an important ecumenical and interfaith role, speaking on behalf of Anglicans in England and worldwide.The Archbishop's main residence is Lambeth Palace in the London Borough of Lambeth. He also has lodgings in the Old Palace, Canterbury, located beside Canterbury Cathedral, where The Chair of St. Augustine sits.
As holder of one of the "five great sees" (the others being York, London, Durham and Winchester), the Archbishop of Canterbury is ex officio one of the Lords Spiritual of the House of Lords. He is one of the highest-ranking men in England and the highest ranking non-royal in the United Kingdom's order of precedence.
Since Henry VIII broke with Rome, the Archbishops of Canterbury have been selected by the English (British since the Act of Union in 1707) monarch. Today the choice is made in the name of the Sovereign by the prime minister, from a shortlist of two selected by an ad-hoc committee called the Crown Nominations Commission. Since the twentieth century, the appointment of Archbishops of Canterbury conventionally alternates between Anglo-Catholics and Evangelicals.
The current archbishop, the Most Reverend and Right Honourable Rowan Douglas Williams, is the 104th Archbishop of Canterbury. He was enthroned at Canterbury Cathedral on 27 February 2003. As archbishop he signs himself as + Rowan Cantuar. Immediately prior to his appointment to Canterbury he was the Bishop of Monmouth in Wales. Whilst at Monmouth he was later, for a shorter period, also the Archbishop of Wales.
In addition to his office, the Archbishop also holds a number of other positions; for example, he is Joint President of the Council of Christians and Jews in the UK. Some positions he formally holds ex officio and others virtually so (the incumbent of the day, although appointed personally, is appointed because of his office). Amongst these are:
It has been suggested that the Roman province of Britannia had four archbishops, seated at London, York, Lincoln and Cirencester.  However, in the 5th and 6th centuries Britannia began to be overrun by pagan, Germanic peoples who came to be known collectively as the Anglo-Saxons. Of the kingdoms they created, Kent arguably had the closest links with European politics, trade and culture, due to the fact that it was conveniently sited for communication with the Continent. In the late 6th century, King Æthelberht of Kent married a Christian Frankish princess named Bertha, possibly before becoming king, and certainly a number of years before the arrival of the first Christian mission to England. He permitted the preaching of Christianity.
The first Archbishop of Canterbury was St. Augustine, who arrived in Kent in 597 AD, having been sent by Pope Gregory I on a mission to the English. He was accepted by King Æthelbert, on his conversion to Christianity, in about the year 598. It seems that Pope Gregory, ignorant of recent developments in the former Roman province, including the spread of the Pelagian heresy, had intended the new archiepiscopal sees for England to be established in London and York. In the event, Canterbury was chosen instead of London, owing to political circumstances. Since then the Archbishops of Canterbury have been referred to as occupying the Chair of St. Augustine.
Before the break with papal authority in the 16th century, the Church of England was an integral part of the Western European Church. Since the break the Church of England, an established national church, still considers itself part of the broader Western Catholic tradition as well as being the "mother church" of the worldwide Anglican Communion, though no longer in communion with the See of Rome.
The Archbishop of Canterbury exercises metropolitical (or supervisory) jurisdiction over the Province of Canterbury, which encompasses thirty of the forty-four dioceses of the Church of England, with the rest falling within the Province of York. The four dioceses of Wales were formerly also under the Province of Canterbury until 1920 when they were transferred from the established Church of England to the disestablished Church in Wales.
The Archbishop of Canterbury has a ceremonial provincial curia, or court, consisting of some of the senior bishops of his province. The Bishop of London - the most senior cleric of the church with the exception of the two archbishops - serves as Canterbury's Provincial Dean, the Bishop of Winchester as Chancellor, the Bishop of Lincoln as Vice-Chancellor, the Bishop of Salisbury as Precentor, the Bishop of Worcester as Chaplain and the Bishop of Rochester as Cross-Bearer.
Along with primacy over the Archbishop of York, the Archbishop of Canterbury also has a precedence of honour over the other archbishops of the Anglican Communion. He is recognised as primus inter pares, or first amongst equals. The Archbishop of Canterbury, however, does not exercise any direct authority in the provinces outside England.
At present the archbishop has four suffragan bishops:
The Archbishop of Canterbury and the Archbishop of York are both styled as "The Most Reverend"; retired archbishops are styled as "The Right Reverend". Archbishops are, by convention, appointed to the Privy Council and may, therefore, also use "The Right Honourable" for life (unless they are later removed from the council). In formal documents, the Archbishop of Canterbury is referred to as "The Most Reverend Father in God, Forenames, by Divine Providence Lord Archbishop of Canterbury, Primate of All England and Metropolitan". In debates in the House of Lords, the archbishop is referred to as "The Most Reverend Primate, the Archbishop of Canterbury". "The Right Honourable" is not used in either instance. He may also be formally addressed as "Your Grace" - or, more often these days, simply as "Archbishop", "Father" or (in the current instance) "Dr Williams".
The surname of the Archbishop of Canterbury is not always used in formal documents; often only the first name and see are mentioned. The archbishop is legally entitled to sign his name as "Cantuar" (from the Latin for Canterbury). The right to use only a title as a legal signature is only permitted to bishops and Peers of the Realm. The current Archbishop of Canterbury usually signs as "+ Rowan Cantuar".
In the order of precedence, the Archbishop of Canterbury is ranked above all individuals in the realm, with the exception of the Sovereign and members of the Royal Family.  Immediately below him is the Lord Chancellor and then the Archbishop of York.
The Archbishop of Canterbury's official residence in London is Lambeth Palace. Until the 19th century there were also major residences at Croydon Palace and Addington Palace. At one time there was also a palace in Maidstone in Kent, now called the Archbishop's Palace. There are ruins of another former palace at Otford in Kent.