In Quidditch Through the Ages, it says that the first ever World Cup was in 1473, with a match being held every 4 years. Yet the World Cup in 1994 is number 422. There can't be 422 world cups in 521 years with a four-year gap in between. Calculated correctly, the World Cup that the Weasleys, Hermione, and Harry attend is actually the 131st, and it should have been held in 1993.