A revolution in Portugal in 1820 invites the King to return to Europe to accept the Constitution put forward by the revolutionary junta of Lisbon. The monarch leaves his son, Dom Pedro de Alcantara, in Brazil, and quits the country. It is said that on bidding Dom Pedro farewell he cried: "Before long Brazil will separate from Portugal; if it is so, crown yourself before some adventurer gets hold of the sceptre."

The Lisbon Parliament wished to destroy the reforms of João VI. in Brazil, and to transform a monarchical nation into a feudal colony, but the Brazilian deputies then in Portugal protested and emigrated to England. A revolution at Pernambuco in 1817 had raised the standard of nationalism. The manifesto or Preciso of the revolutionaries formulated the complaints of the colony. "There is no longer any distinction," said the victorious patriots, "between Brazilians and Europeans; all consider themselves brothers; as descendants of the same origin, as inhabitants of the same country, as believers of the same religion."

Journalism, in its infancy, was propagating constitutional ideas both in the north and in the south. Jacobin declamation and romantic ideology created a powerful movement in the taciturn colony. Governmental juntas were appointed in the provinces. Portuguese and Brazilians struggled for political and social domination, but a Lusitanian army, in spite of popular protest, imposed the oath of fidelity to the Constitution which had been promulgated for the metropolis by the distant Cortes.

The prince prevented a federal disaggregation and founded the unity of Brazil. He united the representatives of the rebellious provinces, convoked, in 1822, a Constituent Assembly, visited the country districts, and became the "perpetual defender of Brazil." Like the Gothic kings at the time of the Moorish invasion, or the French princes who were faced with feudal anarchy, he founded a national dynasty, and bound the unity and independence of Brazil with the destinies of the monarchy. Dom João VI. had raised Brazil to the rank of a kingdom; Pedro I. rendered it independent of Portugal. "Independence or death!" he cried, in his triumphant Odyssey across the rebellious provinces. At Ipiranga floated the new flag, gold and green, of the new-born Empire. Pedro I. was crowned Constitutional Emperor in December, 1822.

José Bonifacio Andrade e Silva, naturalist, philosopher, and soldier, an encyclopædist according to the French tradition, was the minister of this national transformation; he condemned the revolution, having previously supported natural rights and excessive liberties. He suppressed the journals, and the monarch dissolved the Constituent Assembly, whose violence and lyrical propensities were not a help to the political action of a conservative minister.

Extreme groups were formed which the Emperor endeavoured to conciliate: reactionaries who wanted an absolute government, idealists who wished for a republic, moderates, and conciliatory monarchists who sought a gradual progress under a stable government. Weary of revolutions the Emperor inaugurated a despotic régime; he withdrew from the Assembly, exiled the rebels, among others Andrade, now radical but formerly a reactionary, and always greedy for power. He surrounded himself with Portuguese troops, and the new nobility, the filhos do reinho, and the press attacked him in the name of nationalism. It demanded the persecution of favourites, as in the Spanish colonies the expulsion of the old ruling classes was decreed.

The Emperor once again united the moderate parties, and demanded a Constitution, to which the country swore allegiance in 1824; it was a constitutional charter, an imitation of the liberal European charters. In 1826 he convoked a new National Assembly. Revolutions were still disturbing the country; some provinces wished to secede from the new kingdom; Pernambuco was always the centre of liberalism. An old patriot, Paez de Andrade, hoped to unite the Northern States of Brazil in the "Confederation of the Equator." The monarch sent troops to the north to intimidate the country, and the Lower Chamber condemned this act of despotism; a radical priest, Diego Antonio Feijó, led the radical opposition. He was a revolutionary in Parliament, demanding a responsible government, and condemning the ministers who forced peace upon the provinces by means of foreign legions, German and Irish mercenaries.

The Chambers were invaded by republicans and federals, and Pedro I. by no means abandoned his reactionary ministers. These latter succeeded one another in a series of perpetual crises. The external warfare complicated the political situation; Uruguay had revolted, counting on the aid of Argentine regiments. The Brazilians were defeated, and recognised the independence of Uruguay by the treaty of 1828.

King João died in 1826, and the Emperor remained undecided between the traditional kingdom and the new Empire. He formed a liberal Cabinet to satisfy radicals and federalists, who had triumphed at the elections of 1830. A useless transaction: ministries fell, and the financial muddle increased. The people of Rio de Janeiro revolted, and the Emperor abdicated. José Bonifacio, creator of the political régime, was to be the tutor of the infant prince.

The Regency was a moderate government which steered clear of reactionaries and exaltés both, of absolutism and republicanism. Father Feijó, minister of the Regency, became, like many radicals, a conservative; he organised the National Guard, suppressed military meetings and enforced peace in the interior. Subversive movements continued, and the invulnerable minister repressed them. The administration of the country progressed, schools were founded, the Assembly issued wise codes of laws. The Regent, Andrade, imprisoned and deposed, Diego Feijó was elected tutor of the prince in 1835; the old radical politician was now dictator. He represented the moderates as against the revolutionists; in extreme cases he abandoned liberalism for autocracy. As early as 1836 his political autocracy began to decline and the liberal campaign gathered force. Feijó passed over the regency to his friend, Aranjo Lima, and left the Government. This representative of authority in a country which was a prey to anarchy was autocratic by virtue of his patriotism; like all American dictators he stifled revolution in its blood.