Early in 1818 Colburn wrote to suggest that the Morgans should proceed to Italy with a view to collaborating in a book on that country, and offered them the handsome sum of £2000 for the copyright. By this time Sir Charles had lost most of his practice, owing to his publication of a scientific work, The Outlines of the Physiology of Life, which was considered objectionably heterodox by the Dublin public. There was no obstacle, therefore, to his leaving home for a lengthened period, and joining his wife in her literary labours. In May, the pair journeyed to London en route for the South, Lady Morgan taking with her the nearly finished manuscript of a new novel, Florence Macarthy. With his first reading of this book Colburn was so charmed, that he presented the author with a fine parure of amethysts as a tribute of admiration.

According to the testimony of impartial witnesses, Lady Morgan made as decided a social success in Italy as she had done a couple of years earlier in France. Moore, who met the couple in Florence, notes in his diary for October 1819: 'Went to see Sir Charles and Lady Morgan; her success everywhere astonishing. Camac was last night at the Countess of Albany's (the Pretender's wife and Alfieri's), and saw Lady Morgan there in the seat of honour, quite the queen of the room.' In Rome the same appreciation awaited her. 'The Duchess of Devonshire,' writes her ladyship, 'is unceasing in her attentions. Cardinal Fesche (Bonaparte's uncle) is quite my beau.... Madame Mère (Napoleon's mother) sent to say she would be glad to see me; we were received quite in an imperial style. I never saw so fine an old lady--still quite handsome. The pictures of her sons hung round the room, all in royal robes, and her daughters and grandchildren, and at the head of them all, old Mr. Bonaparte. She is full of sense, feeling, and spirit, and not the least what I expected--vulgar.'

Florence Macarthy was published during its author's absence abroad. The heroine, Lady Clancare, a novelist and politician, a beauty and a wit, is obviously intended for Lady Morgan herself, while Lady Abercorn figures again under the title of Lady Dunore. But the most striking of all the character-portraits is Counsellor Con Crawley, who was sketched from Lady Morgan's old enemy, John Wilson Croker. According to Moore, Croker winced more under this caricature than under any of the direct attacks which were made upon him. Con Crawley, we are told, was of a bilious, saturnine constitution, even his talent being but the result of disease. These physical disadvantages, combined with an education 'whose object was pretension, and whose principle was arrogance, made him at once a thing fearful and pitiable, at war with its species and itself, ready to crush in manhood as to sting in the cradle, and leading his overweening ambition to pursue its object by ways dark and hidden--safe from the penalty of crime, and exposed only to the obloquy which he laughed to scorn. If ever there was a man formed alike by nature and education to betray the land which gave him birth, and to act openly as the pander of political corruption, or secretly as the agent of defamation; who would stoop to seek his fortune by effecting the fall of a frail woman, or would strive to advance it by stabbing the character of an honest one; who could crush aspiring merit behind the ambuscade of anonymous security, while he came forward openly in defence of the vileness which rank sanctified and influence protected--that man was Conway Crawley.'

The truth of the portraiture of the whole Crawley family--exaggerated as it may seem in modern eyes--was at once recognised by Lady Morgan's countrymen. Sir Jonah Barrington, an undisputed authority on Irish manners and character, writes: 'The Crawleys are superlative, and suffice to bring before my vision, in their full colouring, and almost without a variation, persons and incidents whom and which I have many a time encountered.' Again, Owen Maddyn, who was by no means prejudiced in Lady Morgan's favour, admits that her attack on Croker had much effect in its day, and was written on the model of the Irish school of invective furnished by Flood and Grattan. As a novelist, he held that she pointed the way to Lever, and adds: 'The rattling vivacity of the Irish character, its ebullient spirit, and its wrathful eloquence of sentiment and language, she well portrayed; one can smell the potheen and turf smoke even in her pictures of a boudoir.' In this sentence are summed up the leading characteristics, not only of Florence Macarthy, but of all Lady Morgan's national romances.

Italy was published simultaneously in London and Paris in June, 1821, and produced an even greater sensation than the work on France, though Croker declared that it fell dead from the press, and devoted the greater part of his 'review' in the Quarterly to an analysis of Colburn's methods of advertisement. Criticism of a penal kind, he explained, was not called for, because, 'in the first place, we are convinced that this woman is wholly incorrigible; secondly, we hope that her indelicacy, vanity, and malignity are inimitable, and that, therefore, her example is very little dangerous; and thirdly, though every page teems with errors of all kinds, from the most disgusting to the most ludicrous, they are smothered in such Boeotian dulness that they can do no harm.' In curious contrast to this professional criticism is a passage in one of Byron's letters to Moore. 'Lady Morgan,' writes the poet, 'in a really excellent book, I assure you, on Italy, calls Venice an ocean Rome; I have the very same expression in Foscari, and yet you know that the play was written months ago, and sent to England; the Italy I received only on the 16th.... When you write to Lady Morgan, will you thank her for her handsome speeches in her book about my books? Her work is fearless and excellent on the subject of Italy--pray tell her so--and I know the country. I wish she had fallen in with me; I could have told her a thing or two that would have confirmed her positions.'

Almost simultaneously with the appearance of Italy, Colburn printed in his New Monthly Magazine a long, vehement, and rather incoherent attack by Lady Morgan upon her critics. The editor, Thomas Campbell, explained in an indignant letter to the Times, that the article had been inserted by the proprietor without being first submitted to the editorial eye, and that he was in no way responsible for its contents. Colburn also wrote to the Times to refute the Quarterly reviewer's statements regarding the sales of Italy, and publicly to declare his entire satisfaction at the result of the undertaking, and his willingness to receive from the author another work of equal interest on the same terms. In short, never was a book worse reviewed or better advertised.

The next venture of the indefatigable Lady Morgan, who felt herself capable of dealing with any subject, no matter how little she might know of it, was a Life of Salvator Rosa. This, which was her own favourite among all her books, is a rather imaginative work, which hardly comes up to modern biographical standards. The author seems to have been influenced in her choice of a subject rather by the patriotic character of Salvator Rosa than by his artistic attainments. Lady Morgan was once asked by a fellow-writer where she got her facts, to which she replied, 'We all imagine our facts, you know--and then happily forget them; it is to be hoped our readers do the same.' Nevertheless, she seems to have taken a good deal of trouble to 'get up' the material for her biography; it was in her treatment of it that she sometimes allowed her ardent Celtic imagination to run away with her. About this time Colburn proposed that Sir Charles and Lady Morgan should contribute to his magazine, The New Monthly, and offered them half as much again as his other writers, who were paid at the rate of sixteen guineas a sheet. For this periodical Lady Morgan wrote a long essay on Absenteeism and other articles, some of which were afterwards republished.

In the spring of 1824 the Morgans came to London for the season, and went much into the literary society that was dear to both their hearts. Lady Caroline Lamb took a violent fancy to Lady Morgan, to whom she confided her Byronic love-troubles, while Lady Cork, who still maintained a salon, did not neglect her old protégée. The rough notes kept by Lady Morgan of her social adventures are not usually of much interest or importance, as she had little faculty or inclination for Boswellising, but the following entry is worth quoting:--

'Lady Cork said to me this morning when I called Miss ---- a nice person, "Don't say nice, child, 'tis a bad word." Once I said to Dr. Johnson, "Sir, that is a very nice person." "A nice person," he replied; "what does that mean? Elegant is now the fashionable term, but it will go out, and I see this stupid nice is to succeed to it. What does nice mean? Look in my Dictionary; you will see it means correct, precise."'

At Lydia White's famous soirées Lady Morgan met Sydney Smith, Washington Irving, Hallam, Miss Jane Porter, Anacreon Moore, and many other literary celebrities. Her own rooms were thronged with a band of young Italian revolutionaries, whose country had grown too hot to hold them, and who talked of erecting a statue to the liberty-loving Irishwoman when Italy should be free. Dublin naturally seemed rather dull after all the excitement and delights of a London season, but Lady Morgan, though she loved to grumble at her native city, had not yet thought of turning absentee herself. Her popularity with her countrymen (those of her own way of thinking) had suffered no diminution, and her national celebrity was proved by the following verse from a ballad which was sung in the Dublin streets:--