In English Wikipedia, 272 hoaxes were found that lasted longer than a year. Record - 10 years and 1 month
John Robisho was born in 1866 in the city of Thibodeau, New Orleans, and died in 1939 in Louisiana. He was an American musician, drummer and violinist, as well as the leader of his own jazz band.
And Jack Robisho is the hero of a fake Wikipedia article, a fictional serial rapist from the same state. An article about it was created on July 31, 2005, and it lasted until September 3, 2015 - ten years and one month.

John Robisho Orchestra
Guillermo Garcia was an influential oil magnate in the 18th century who lived in South America. But fictional. An article about him lasted from November 17, 2005 to September 19, 2015 - nine years and ten months. Wikipedia editors did not find a single reliable source that would confirm the existence of this character.
The Australian Aboriginal deity, Jar'Edo Wens, is another, this time twice fictional character, who was dedicated to the Wikipedia article on May 29, 2005. Moreover, it was translated for the French section of Wikipedia. The deity received a modified version of the name Jared Owens (Jared Owens). Prior to the removal of Jack Robisho and Guillermo Garcia, Jar'Edo Wens held first place among the oldest fake articles - nine years and nine months.

In the caves of Kimberley, Australia, you will not find images of the deity Jar'Edo Wens
Pikes on Cliffs - this is a fictional place, a house on the coast with a forge and a well. A 16th-century sailor, William Simms, swam ashore after a death sentence imposed by Sir Francis Drake. No one saw this house, and the facts of the existence of that same sailor were not found. The article was deleted nine years and eight and a half months after its creation.

The north coast of Estaca de Bares, Spain, where the house Pikes on Cliffs was supposed to be
It is easy to imagine that in the 1960s in the UK there was a group whose members barked while performing musical compositions. Perhaps this is why the article about The Doggs lasted nine years and eight months. The article was deleted as “Outright hoax”, although on the network you can find one song by artists of the time The Doggs - Billy's gotta run. They did not bark at her.

Gregory Namoff was born February 26, 1924 in Great Neck, New York, and died October 12, 2002 in Boca Rato, Florida. He was an "internationally renowned" investment banker. In 1974, he became a member of the Watergate scandal, but was not found guilty. In the early 1980s, he turned his attention to computers, invested in Apple Computer and Microsoft, and sold his company GN Limited. In 1998, he ran for the US Senate against Bob Graham, but his rival campaigned to connect Nammoff with Nixon and Watergate. In 2002, Nemoff died due to lupus erythematosus.
Wikipedia editors could not confirm a single fact from the paragraph above. This man has never been.

Members of the Watergate scandal
In September 2005, one of the Wikipedia users had few real television programs, so he created an article about the Double Hour show. In this non-existent program, the presenters talked about historical events for two hours.
In total, more than 270 hoaxes have been hanging on Wikipedia for more than a year. Among them are articles about professors from the University of Berkeley, about animation shows, music groups, poets, a note in an article about Lord Byron about his pets - a crocodile and a badger. Wikipedia warns: do not create fake articles, otherwise you will be blocked.