Domitila (or Domitília) de Castro do Canto e Melo[a] (27 December 1797 — 3 November 1867), 1st Viscountess with designation as a Grandee, then 1st Marchioness of Santos, was a Brazilian noblewoman and the long-term mistress and favorite of Emperor Pedro I.

On 13 January 1813, Domitila, at the age of fifteen, married an officer from the second squad of the Corps of Dragons in the city of Vila Rica (now Ouro Preto), Ensign Felício Pinto Coelho de Mendonça (26 February 1790 – 5 November 1833),[6] cited by several historians as a violent man, who beat and raped her, and from whom she divorced on 21 May 1824.

Felício managed to transfer his post in the army from Vila Rica to Santos and settled in São Paulo, trying to reconcile with his wife and in 1818 they returned to live together.

Domitila's detractors would accuse her after being assaulted because she betrayed Felício, when in reality, through documentation and witnesses in the divorce process, he had tried to kill her to sell the land that both, with the death of his mother, had jointly inherited in Minas Gerais.

Outraged by this "interference with his acts as ruler", and influenced by whose defended the break with the metropolis, especially by José Bonifácio de Andrada, he decided to separate the Kingdom of Portugal and the Algarves.

In addition to these liaisons, Domitila's own sister, Maria Benedita de Castro do Canto e Melo, Baroness of Sorocaba, also had a son with Dom Pedro.

In 1826, she received as a gift the "Casa Amarela", as her mansion became known, at number 293 of the current Avenida D. Pedro II, near Quinta da Boa Vista, in São Cristóvão (where the Museum of the First Reign now operates).

[13] The Emperor bought the house from Dr. Teodoro Ferreira de Aguiar and ordered a renovation in a neoclassical style to the architect Pierre Joseph Pézerat.

Already since 1827 he had been looking for a noble blood bride but the sufferings caused to his late wife by him and the scandalous link with the Marchioness of Santos were seen with horror by European courts and several princesses refused to marry the Emperor.

The Austrian ambassador to Rio de Janeiro, Baron Wenzel Philipp von Mareschal, wrote to Vienna about the future marriage of the Emperor and the banishment of the mistress: "Emperor D. Pedro was eventually convinced that the presence of the Lady of Santos would always be inopportune and that a simple change of residence would not satisfy anyone; he insisted on the sale of her properties, the which I heard was already provided and on her departure to São Paulo in eight or ten days".

Rafael Tobias de Aguiar was not only a politician, but also a wealthy Sorocaban farmer: the base of his fortune was the trade in mules, but in time he ended up diversifying his business with sugar farms, cattle and horse breeding.

In 1842, as one of the main leaders of the Liberal Revolution, after his marriage to the Marchioness of Santos and the eminent invasion of Sorocaba by the troops of Luís Alves de Lima e Silva, he fled to the south where he was captured.

Domitila, on hearing of his arrest, arrived to the Imperial court where, by means of a representative, she pleaded to the Emperor that she could live with her husband in the Fortress of Laje to take care of his health, which was granted.

Domitila de Castro do Canto e Melo, Marchioness of Santos died of enterocolitis in her residence in the Rua do Carmo, now Roberto Simonsen, near the Pátio do Colégio, on 3 November 1867 aged 69.

Her grave in the Cemitério da Consolação, as well the two other plots she bought adjoining her gravesite —where her younger brother Francisco de Castro do Canto e Melo, her son Felício Pinto Coelho de Mendonça e Castro, and, after a recent discovery, her daughter the Countess of Iguaçu, were also buried[33]—, were all recovered in the 1980s by the Italian accordionist Mario Zan, one of Domitila's most famous and fervent admirers; he took care of the deposit for the maintenance of the gravesites for years and when he died in 2006 he was buried in a tomb in front of the Marchioness.

Among the legends is that she protects the prostitutes of the city and, due to having achieved a good marriage and restructuring worthily after her scandalous relationship with Emperor Pedro I of Brazil, she became an inspiration for girls who wanted to marry well.