Although many believe Wilde was put in prison for homosexuality, the official charge was gross indecency. He actually started the trials himself, after multiple threats and insults from his lover Alfred Douglas's father,John Sholto Douglas, 9^th Marquess of Queensberry. Queensbury accused Wilde of posing as a sodomite, and Wilde sued him for libel. Although the opposing lawyer used Wilde's writings to suggest that Wilde was a homosexual, he was able to deny these claims. However, after Queensbury made a deal with male prostitutes to testify against Wilde, he lost the libel case. After this, Wilde went bankrupt from legal fees and was eventually arrested on the charge of "gross indecency", which is a misdemeanor charge, less serious than sodomy. This lesser charge was due to the Labouchère Amendment, which states that any man who commits gross indecency with a man is guilty of a misdemeanor, and sentenced to no more than 2 years in prison. In April of 1895, three hearings took place, in which Wilde's sexual partners were paid by the prosecution to testify against him. Despite a weak case against Wilde, with one witness being proven unreliable and a jury who struggled to reach a verdict, Wilde was found guilty of gross indecency and recieved the maximum sentence of 2 years in prison with hard labor. Wilde began serving his prison sentence on May 25, 1895.

Sources:

http://www.branchcollective.org/?ps_articles=andrew-elfenbein-on-the-tri...