The diligence of Niebuhr, though often impeded by illness, was immense. Languages, philosophy, history, natural science, all took their turn. His number of languages was not short of twenty at this time, and in some he was profoundly versed—in most, very respectably. But the most remarkable thing through life was his memory, and its wonderful combination of retentiveness and readiness. This, rather than the imaginative power, it was that made his descriptions so graphic. Seeing and retaining everything, he painted as if all history was before him. When he spoke of a striking event, the coast, the mountain-line, or the plain, all the accompaniments rose up and were grouped before him. You felt carried away with him, as if he had lived there, and was taking you up by the way.
His return to Denmark took place late in 1799. A double appointment awaited him at Copenhagen—two government offices, neither bringing in a large salary, but sufficient to allow of his marrying; and accordingly Amelia Behrens became his wife in May 1800. The five following years found him engaged in the civil service at Copenhagen—sometimes in very onerous and uncongenial duties, sometimes in a position of peril, for the bombardment of the city under Nelson took place in 1801, and he keenly entered into every political incident. During this period of five years, his official service was more than once changed, but it seems always to have been connected with finance. He still found time for study, straining every power of his mind, he says, at one time in investigating Roman history, sure 'that the representations of all the moderns, without exception, are but mistaken, imperfect glimpses of the truth.' This Copenhagen life allowed him time but for one visit to his parents; and a disappointment which annoyed him considerably, in what, he thought, a just expectation of preferment, disposed him, in 1806, to accept an offer from the Prussian government of a post at Berlin not unlike that he had occupied in Copenhagen, but promising many advantages in society and literary opportunities.
Never was there a more disastrous commencement of a new career. The Niebuhrs reached Berlin in October 5, 1806, and on the 14th came the dreadful battles of Jena and Auerstadt, while Napoleon, with his conquering army, marched rapidly upon the city, and seven of the Prussian ministers gave in their allegiance to the French without even the ceremony of communicating with their king. The new bank-director shared in the general misfortune, and was forced to fly, with the court and ministry, first to Danzig, then to Konigsberg, afterwards to Memel and Riga. A fearful time it was; yet still Niebuhr could write soothingly to his parents: 'You must not be uneasy: I can earn a living either as a scholar or a merchant; and if I do not succeed in one country, I shall in another.' To Mme Hensler also he wrote cheeringly, but under caution, for all letters were unsafe. In the meantime, the indefatigable student took the opportunity of learning Russian and Sclavonic.
It is difficult to follow out his course distinctly during the next three and a half trying years. He was always employed in the finance department, and for some little time was a privy-councillor; but he differed widely in his views from some of those with whom he worked. His letters shew the most conscientious desire to put aside every thought of personal ease, and to avert from the poor people around, if possible, some part of the calamity which hostile armies and bad government entailed on them; and it is delightful to observe his perfect honesty and plainness of speech as a statesman—his high ideas of truthfulness in all things. Yet they were mournful years; and his health at last thoroughly failing, he sent in his resignation to the king of Prussia, and solicited the office of historiographer, vacant by the death of Müller. This was granted; and in 1810, he and his wife once more found a settled home at Berlin.
And now came the happiest time of his life; though the great delicacy of his wife's health was an obstacle to the feeling of security, and though still the menaces of Napoleon sounded fearfully loud, if not close at hand. The breathing-time, however, was delightful. The university of Berlin was now just opened, and thither came intelligent professors, men of renown in art and science, in knowledge and wisdom. As historiographer to the king, Niebuhr's part was to lecture on history; and now, for the first time, the treasures he had long been amassing came into direct use as the means, through his management, of instructing other minds. He had never before delivered public lectures, and his advantages in manner were not great; but the success of his first essays on the history of Rome, proves how solid and real must have been the information he had to bestow. He was attended not merely by the young men, but by members of the academy, by professors, by military and public men of all grades. It is no wonder that he succeeded thus: he was half a Roman by nature and feeling.
So passed the happy years of his professorship. But again the noise of war was heard, and he and all his coadjutors had to take up arms, and fight the battle of Prussia against the great tyrant of Europe. Most touching anecdotes are told of the bravery and fine behaviour of the native troops. Perhaps no war was ever more nobly sustained, and with such anxious avoidance of cruelty. What a moment it was to Prussia when the news of Bonaparte's abdication reached the country! when there might be some hope of reaping the harvests they had sown, and rebuilding their ruined villages! But the Niebuhrs were never again to know the calm and happy days they had enjoyed. Mme Niebuhr, who had long been declining, was grievously changed for the worse by the anxieties of the war. On the 2d of May 1815, her husband received at Berlin news of his father's death; and on the 21st of June, his beloved Amelia followed. The good Mme Hensler, who had taken alarm, was near to soothe her last hours, and to comfort the husband. Niebuhr had never spoken to his wife of her approaching end: though longing to know her parting wishes, he dared not break the physician's orders against excitement. Once only, a few days before her death, as he was holding her in his arms, he asked her if there was nothing he could do for her sake—no pleasure he could give her. She replied, with a look of unutterable love: 'You shall finish your history whether I live or die!'
They had no family—he was therefore left alone. At first, nature gave way, and it seemed as if he had imbibed his wife's disease—pulmonary consumption—and that he regarded the legacy as a blessing; but his higher nature triumphed. He promised Mme Hensler to live, and try to accomplish his Amelia's wishes, and she, by her kindly influence, won him to something more. She saw that to him a lonely life was nearly impossible, and she had another partner in store for him—Gretchen Hensler, a niece of her late husband. Again he took her counsel; and again, which is perhaps the most extraordinary part of the affair, it proved that she had judged as well for both parties as possible. There was no concealment in the matter; the new Mme Niebuhr perfectly understood his character and his sorrow—understood that she could not be to him what Amelia had been; but she married him in faith and hope, and the life she brought him was peaceful and ultimately happy.
Then another change had to be made. He could no longer bear Berlin. Every one saw that a different position was desirable, and what better than a residence in that country which his literary labours had seemed to mark out as his own? The king of Prussia wanted an ambassador at Rome, to negotiate with the pope certain matters touching the interests of his Catholic subjects, and Niebuhr's appointment was the most natural one possible.
His first impressions of Rome were not favourable, and his first letter was even querulous; but soon his clear single mind grew strong again; and the spirit of his correspondence during the whole seven years of his Roman residence is delightful. Children brought out the fatherly part of his character; his wife was ever his loving and devoted companion; some powerful and interesting minds sought his companionship; and a taste for art was improved by intercourse with the rising young artists who were then at Rome—Cornelius, Overbeck, Schadow; but, above all, the education of Marcus, his eldest child and only boy, who can wonder if he became more and more of a Roman, and if he closed the seventh year of his residence mournfully when preparing for his return to Germany?
His mission had been a difficult one—not that the papal court was unfriendly, but the home instructions were not always clear and consistent. An earnest Protestant himself, he was yet profoundly alive to the duties of rulers towards all their subjects, of all religious beliefs, and wished in every negotiation to make sure of a large measure of real freedom.