The quinquennial Neronia was a massive Greek-style festival created by the Roman Emperor Nero. It consisted of three parts: first music, oratory and poetry, second gymnastics and the last horseriding.
The Neronia were a quinquennial event, which in this case wasn't counted inclusively but exclusively as the event took place every five years. The first Neronia was held in 60, 6 years after Nero's accesstion in 54, the second in 65. Nero's death and damnatio memoriae prevented a third installment.