Herculano received his early education, comprising Latin, logic and rhetoric, at the Necessidades Monastery, and spent a year at the Royal Marine Academy studying mathematics with the intention of entering on a commercial career.

The stirring incidents in the political emancipation of Portugal inspired his muse, and he describes the bitterness of exile, the adventurous expedition to Terceira, the heroic defence of Porto, and the final combats of liberty.

In 1837 he founded the Panorama in imitation of the English Penny Magazine, and there and in Illustração he published the historical tales which were afterwards collected into Lendas e Narrativas; in the same year he became royal librarian at the Ajuda Palace, which enabled him to continue his studies of the past.

The Panorama had a large circulation and influence, and Herculano's biographical sketches of great men and his articles of literary and historical criticism did much to educate the middle class by acquainting them with the story of their nation, and with the progress of knowledge and the state of letters in foreign countries.

Serious students in Portugal and abroad welcomed the book as an historical work of the first rank, for its evidence of careful research, its able marshalling of facts, its scholarship and its painful accuracy, while the sculptural simplicity of the style and the correctness of the diction made it a Portuguese classic.

[2] The first volume, however, gave rise to a celebrated controversy, because Herculano had reduced the famous battle of Ourique, which was supposed to have seen the birth of the Portuguese monarchy, to the dimensions of a mere skirmish, and denied the apparition of Christ to King Afonso, a fable first circulated in the 15th century.

In a letter to the cardinal patriarch of Lisbon entitled Eu e o Clero (1850), he denounced the fanaticism and ignorance of the clergy in plain terms, and this provoked a fierce pamphlet war marked by much personal abuse.

[2] In his youth, the excesses of absolutism had made Herculano a Liberal, and the attacks on his history turned this man, full of sentiment and deep religious conviction, into an anti-clerical who began to distinguish between political Catholicism and Christianity.

[2] The alliance of Liberalism and Catholicism, represented by Herculano and his fellow poetic historians Chateaubriand and Lamartine had ended as the movement known as Ultramontanism grew within the Catholic hierarchy after the Revolutions of 1848.

In politics he remained a constitutional Liberal of the old type, and, for him, the people were the middle classes in opposition to the lower, which he saw to have been the supporters of tyranny in all ages, while he considered radicalism to mean a return via anarchy to absolutism.

A rare capacity for tedious work, a dour Catonian rectitude, a passion for truth, pride, irritation when criticized, and independence of character are the marks of Herculano as a man.

A lack of imagination and a deficit of the philosophic spirit prevented him from penetrating or drawing characters, but his analytical gift, joined to persevering toil and honesty of purpose, enabled him to present a faithful account of ascertained facts and a satisfactorily lucid explanation of political and economic events.