A noite do castelo ("The Night of the Castle") is an opera seria in three acts by the Brazilian Romantic era composer, Antônio Carlos Gomes.

The libretto in Portuguese by Antônio José Fernandes dos Reis was based on António Feliciano de Castilho's 1830 poem of the same name.

In 1860, Gomes wrote a letter from Rio de Janeiro to his father, inviting him to the opening night which would take place the following year: "Meu bom pai.

Hoje mesmo começo a trabalhar na composição da ópera, prepare-se portanto, para vir ao Rio de Janeiro em 1861.

")The first performance of A noite do castelo by the Opera Lyrica Nacional at the Theatro Lyrico Fluminense on September 4, 1861, was loudly applauded, with contemporary accounts describing the audience as being "in delirium".

Gomes was made a Cavalier of the Imperial Order of the Rose on the stage that night with Pedro II himself pinning the medal on the composer.

Raimundo enters and in his aria, "Era Alta Noite" , he tells the story of how, in one terrible night, while he was sitting at the porch of his house, alone, he suddenly heard a strange moan.

When he raised his eyes, he almost died of fright; he saw the ghost of a knight, dressed all in black armor, gazing at the castle and whispering Leonor's name.

When the guests inquire about the identity of the strange knight, Raimundo explains that he is already very old, his eyesight is not quite what it used to be, but that he thinks it was the ghost of Orlando's nephew, Henrique, who apparently had died in the Battle of Mount Zion.

At first, everything is lovely; she and Fernando are enjoying their day together, when suddenly, everything turns into darkness and a demented looking knight appears with a macabre expression on his face and lunges at her.

Suddenly, the dark knight returns and frightens everyone; Count Orlando, Leonor's father, tries to deescalate the situation and offers the stranger a glass of wine, but it is in vain.

After Orlando presses him on what this is all about, the knight goes on to tell a story of two young lovers, who grew up together and where about to be married, when the man was called to battle and had to leave his betrothed behind.