The 19th century opened with crowning events which marked it as a century of conflict between church and state and between religion and reason.

In 1801, Napoleon signed a new concordat with Pius VII in which the state was given a veto over the appointment of bishops by the Pope and over the appointment of lower clergy by the bishops, and Protestants were granted freedom of religion. The Pope had given grudging assent to the revolution and, in 1804, Pius VII sat as a pathetic spectator while Napoleon crowned himself emperor.

Four years later, Napoleon took the papal states and the Pope was soon exiled to Fontainebleau, near Paris.

The experiences were humiliating for the papacy and shook the Church to its core. In France, in previous centuries, Gallicanism had challenged the power of the Popes. In Germany and Austria, there were new challenges from those who argued that the Pope was in fact only the first among equals, and the primary source of authority was church councils.

Once the papacy returned to the Vatican, the Jesuits were reorganised and a new movement, Ultramontanism ("beyond the mountains") arose to promote the supreme authority of the Pope in matters of faith and practice.

However, the Catholic Church continued to face assault from liberal and republican political thought. Pope Gregory XVI and Pope Pius IX fought liberalism and the moves to unite Italy. As a new revolutionary fervour swept France, Italy and Germany, Mazzini and Garibaldi succeeded in forcing Pius IX into exile in 1848. When he returned to Rome two years later, his earlier liberal sympathies had vanished.

As political power ebbed away from Pius, he put increasing emphasis on his spiritual powers. He re-established the Catholic hierarchies in England and the Netherlands, and signed concordats with Russia, Spain and Austria.

In 1854, he proclaimed the doctrine of Mary's Immaculate Conception. In 1864, he issued the Syllabus of Errors in which political liberalism was condemned, along with rationalism, liberal theology, religious toleration, the Bible Societies, civil marriages and freemasonry. And in 1869, he summoned the first Vatican Council.

The council had an in-built majority in favour of the Ultramontanists - 279 Italian bishops and 265 bishops from all other European states - and it strengthened his power inside the church by proclaiming papal infallibility on July 13th, 1870.

The Ultramontanists had triumphed over Gallicanism and the liberal bishops. Pius rebuked one dissenting bishop with the words: "Tradition; I am tradition."

The German church historian Dollinger refused to be silenced and was excommunicated. Yet the Pope's political strength had been irreversibly weakened; in 1870 the city of Rome was incorporated in the new united Italy, leaving the Pope with only the Vatican, the Lateran and Castel Gandolfo from the former papal states.

In France, Napoleon III was forced to choose between Catholicism and the national interest, and chose the latter. In Germany, the Prussian chancellor, Bismarck, initiated the Kulturkampf against the Catholic Church and seriously weakened the legal status of Catholics, leading to the expulsion of the Jesuits and the state taking control of education.

Leo XIII had a calming influence on church-state relations in Germany and in France, where he urged Catholics to abandon royalism and accept the republic. In his encyclical Rerum Novarum (1891), he pleaded for social reform and for trade unionism to ensure workers received a proper wage. The papacy had woken up to the threats and promises of the industrial revolution.

Since its dawning in the 1760s, the industrial revolution was challenging morals and values. While some evangelicals found common cause with the new morality of industrial capitalism, others could see the dismal lot of those who laboured in William Blake's "dark satanic mills" and Charles Dickens's Coketown, with its "interminable serpents of smoke".

The repeal of the Test and Corporation Acts in 1828 and Catholic emancipation in 1829 had given some Catholics and nonconformists in Britain and Ireland the right to vote and to sit in parliament. But the rights and plight of the working class, Catholic or Protestant, had still to be addressed.

At first, the parish system of the Church of England was unable to respond to the industrial revolution and the needs of the new urban masses it had thrown up. But the evangelicalism which had moved William Wilberforce, Fowell Buxton and the "Clapham Sect" to labour for the abolition of the slave trade in 1807 and of slavery in 1833 was the same evangelicalism which, a generation later, worked to ease the hard lot of factory workers.

Christian Socialism first emerged in the writings of Charles Kingsley, better remembered today for The Water Babies and Westward Ho!, and F.D. Maurice. It is often pointed out the Tolpuddle Martyrs were firm Christians and it is frequently repeated that the Labour Party in Britain owed more to Methodism than Marxism. But faced with the challenges of Charles Darwin and Karl Marx, the Church often retreated into itself to address only its own agenda.

The Oxford Movement - led by John Keble, John Henry Newman, Edward Pusey and Henry Manning - was brought together first by their concern at legislative measures aimed at the Church of Ireland. It inspired the great hymns of Newman and Lyte, the architecture of Pugin, the poetry of the Rossettis, the paintings of the pre-Raphaelites and many in the arts and crafts movement.

HOWEVER, as a movement it often appeared more concerned with church order, sacramental life, church architecture and liturgy than with mission and the state of the world. Newman, Manning, Pugin and many others drifted to Rome and it was another generation before Bishop Charles Gore and the essayists who contributed to Lux Mundi found a vibrant combination of theology, mission and politics.

Their circle included the Cambridge New Testament scholar and future Bishop of Durham, Brooke Foss Westcott, first president of the Christian Social Union and one of the early pioneers of historic and literary criticism and of modern theology.

An inward-looking Pietism sometimes broke its bonds: the new movements of the 19th century included the Dublin-born Plymouth Brethren, who typified the temptation to withdraw from the world, but also included the YMCA, founded by George Williams, and the Salvation Army, founded by William Booth.

European continental theology had been enriched in the 19th century by Immanuel Kant, Friedrich Schleiermacher and Soren Kierkegaard. Missionary work saw its frontiers expanded through the labours of men such as David Livingstone. But the church in America was deeply divided by the issue of slavery, while the church in Europe, forced into retreat by the challenges of the industrial revolution and the writings of Darwin and Marx, was weakened by the defensiveness of Pius IX and the inward-looking Pietism which threatened to dominate Protestantism. Was Christianity prepared to face the challenges of the 20th century?