The Catholic Church in Scotland is the Roman Catholic Church's affiliate in Scotland, founded during the Roman Empire. Christianity was introduced to the Scots by Roman soldiers stationed in northern Britannia, and, while it temporarily declined due to the arrival of the pagan Anglo-Saxons, Irish and Scottish missions converted Scotland to Catholicism from the fifth to seventh centuries. The Scottish Church, along with the other Celtic churches, allowed for abbots to be more powerful than the bishops, relaxed the rules about clerical celibacy, and differed from the Roman church on the form of tonsure and calculating the date of Easter. Under Norman rule, the church established local parishes, and the mendicant orders of friars grew and new saints and cults of devotion proliferated. The Scottish Church remained stable until the Reformation of the 16th century, and the Church of Scotland adopted a Calvinist confession in 1560 and split with Rome. The celebration of the Catholic mass was outlawed, but the Catholic Church survived in some parts of the country. By 1600, a third of nobles and gentry were still Catholic, and it became an underground faith across the country. During the 17th century, the Church's organization deteriorated and the faith collapsed, with Presbyterianism becoming the main faith of the country. From 1770 to 1810, landlords cleared the Western Highlands of Catholic tenants, many of whom emigrated to Canada or the other British colonies. During the 19th century, large-scale Irish immigration to Scotland led to a resurgence of Catholicism in Scotland, as did later Italian, Polish, and Lithuanian immigrants. In 1878, Pope Leo XIII re-established the Catholic hierarchy in Scotland, and, by 2011, 16% of Scotland was Catholic, while 32% was Presbyterian.