[2] As secretary to Niebuhr, Bunsen was brought into contact with the Vatican movement for the establishment of the papal church in the Prussian dominions, to provide for the largely increased Catholic population.

He was among the first to realize the importance of this new vitality on the part of the Vatican, and he made it his duty to provide against its possible dangers by urging upon the Prussian court the wisdom of fair and impartial treatment of its Catholic subjects.

[6] After leaving Rome, where he had become intimate with all that was most interesting in the cosmopolitan society of the papal capital, Bunsen went to England, where, except for a short term as Prussian ambassador to Switzerland (1839–1841), he spent the rest of his official life.

Enthusiasm for evangelical religion and admiration for the Anglican Church they held in common, and Bunsen was the instrument naturally selected for realizing the king's fantastic scheme of setting up at Jerusalem a Prusso-Anglican bishopric as a sort of advertisement of the unity and aggressive force of Protestantism.

The Jerusalem bishopric, with the consent of the British government and the active encouragement of the archbishop of Canterbury and the bishop of London, was duly established, endowed with Prussian and English money, and remained for some forty years an isolated symbol of Protestant unity and a rock of stumbling to Anglican Catholics.

[8] During his stay in England Bunsen had made himself very popular among all classes of society, and he was selected by Queen Victoria, out of three names proposed by the king of Prussia, as ambassador to the Court of St. James's.

Bunsen had realized the significance of the signs that heralded these revolutions, and tried in vain to move Frederick William to a policy which would have placed him at the head of a Germany united and free.

[3] With the visionary schemes of Frederick William, whether that of setting up a strict episcopal organization in the Evangelical Church in Prussia, or that of reviving the defunct ideal of the medieval Empire, Bunsen found himself increasingly out of sympathy.

He felt bitterly the humiliation of Prussia by Austria after the victory of the reaction; and in 1852 he set his signature reluctantly to the treaty which, in his view, surrendered the "constitutional rights of Schleswig and Holstein".

On the outbreak of the Crimean War he urged Frederick William to throw in his lot with the western powers, and create a diversion in the north-east which would have forced Russia at once to terms.

In September 1857 Bunsen attended, as the king's guest, a meeting of the Evangelical Alliance at Berlin; and one of the last papers signed by Frederick William, before his mind gave way in October, was that which conferred upon him the title of baron and a peerage for life.

In 1858, at the special request of the regent (afterwards the emperor) William, he took his seat in the Prussian House of Lords, and, though remaining silent, supported the new ministry, of which his political and personal friends were members.

At the same time he carried through the press, assisted by Samuel Birch, the concluding volumes of his work (published in English as well as in German) Egypt's Place in Universal History.

This work contained a reconstruction of Egyptian chronology, together with an attempt to determine the relation in which the language and the religion of that country stand to the development of each among the more ancient non-Aryan and Aryan races.