The Catholic Church in England and Wales is part of the worldwide Roman Catholic Church in full communion with the Pope. Celtic Christianity, with some traditions different from those of Rome, was present in Roman Britain from the first century AD, but after the departure of the Roman legions was in retreat to Paganism. In 597, the first authoritative papal mission, establishing a direct link from the Kingdom of Kent to the See of Rome and to the Benedictine form of monasticism, was carried into effect by Augustine of Canterbury.
The English Church continuously adhered to See of Rome as the Catholic Church in England for almost a thousand years from the time of Augustine of Canterbury, but in 1534, during the reign of King Henry VIII, the church, through a series of legislative acts between 1533 and 1536 became independent from the Pope for a period as the Church of England, a national church with Henry declaring himself Supreme Head. Under Henry's son, Edward VI, the Church of England became more influenced by the European Protestant movement.
The English Church was brought back under full papal authority in 1553, at the beginning of the reign of Queen Mary, and Catholicism was enforced by the Marian persecutions; however, when Queen Elizabeth I came to the throne in 1558, the Church of England's independence from Rome was reasserted through the settlement of 1559, which shifted the Church of England's teaching and practice, and in the Act of Uniformity, which caused a rift between Catholics and Queen. In 1570 Pope Pius V responded, in his papal bull Regnans in Excelsis, calling on all Catholics to rebel against Elizabeth and excommunicating anyone who obeyed her. The Parliament of England made the fact of being a Jesuit or seminarian treasonable in 1571. Priests found celebrating Mass were often hanged, drawn and quartered, rather than being burned at the stake. The Catholic Church (along with other non-established churches) continued in England, although it was at times subject to various forms of persecution. Most recusant members (except those in diaspora on the Continent, in heavily Catholic areas in the north, or part of the aristocracy) practised their faith in private for all practical purposes. In 1766, the Pope recognised the English Monarchy as lawful, and this led eventually to the Roman Catholic Relief Act 1829. Dioceses (replacing districts) were re-established by Pope Pius IX in 1850. Apart from the 22 Latin Rite dioceses, there is the Eastern Catholic diocese of the Ukrainian Catholic Eparchy of Holy Family of London.
In the 2001 United Kingdom census, there were 4.2 million Roman Catholics in England and Wales, some eight per cent of the population. One hundred years earlier, in 1901, they had represented only 4.8 per cent of the population. In 1981, 8.7 per cent of the population of England and Wales were Roman Catholic. In 2009 an Ipsos Mori poll found that 9.6 per cent, or 5.2 million English and Welsh were Catholic. Sizeable populations include North West England where one in five is Catholic, a result of large-scale Irish immigration in the nineteenth century as well as the high number of English recusants in Lancashire.