en.wikipedia.org/wiki/Renaissance_fair

The claim says the original Southern California Renaissance Pleasure Faire was held in spring 1966 at Paramount Ranch. But multiple historical sources place the first actual fair three years earlier, on May 11–12, 1963, at Haskell's Rascals Ranch in North Hollywood.

Evidence:

• A History.com article on the origins of Renaissance fairs states: "On May 11, 1963, they hosted a two-day event called the Renaissance Pleasure Faire and May Market... Held at a North Hollywood summer camp..." It separately says the fair moved to Paramount Ranch by 1965, showing Paramount was not the location of the original event.
• The Faire History archive, which preserves early programs from the original organizers' family, lists "South 1963 ~ Haskells Ranch, North Hollywood" and "South 1965 ~ Paramount Ranch, Agoura Hills". A related Faire History page likewise says: "The first actual 'Faire' opened its two-day run ... on May 11, 1963, at ... Haskell's Rascals Ranch" and that "In 1965, the Renaissance Pleasure Faire found its long-time home ... [at] the Paramount Ranch."

So the sentence appears to conflate the original 1963 fair with a later Paramount Ranch run. If the sentence is meant to describe the first Paramount Ranch edition, 1965 would be the supported year; if it is meant to describe the original fair, the correct date/location is 1963 at Haskell's Rascals Ranch.