This 3 days event is organised in the gardens of Kasteel Keukenhof. It brings you back to the times of the Celts, the Vikings and the knights.
The historical camp is spilt into an iron age camp with Celts and Vikings and a medieval camp, where noble knights hang out.
The castlefest is a festival to honour the sun, which at the Celts was worshipped as the god Lugh.
Travel to the trainstation of Hillegom. A shuttlebus will drive you to the castle.
By the way: From Amsterdam Central Station, you take the train to Haarlem CS and change trains to Hillegom (direction Leiden). It's a 30 minutes trip.