It's always interesting to read of "soft" things like customs lasting, as opposed to "hard" archaeology and architecture. While far simpler, one of my favourites is the Uffington White Horse (https://en.wikipedia.org/wiki/Uffington_White_Horse), which has been regularly re-packed with chalk for at least 2500 years.

That was a 17th century insult aimed at Oliver Cromwell. There's no evidence it's older than the 1600s.