"The Bolton Percy hoard of roughly 4,000 Northumbrian bronze stycas was discovered in two portions 120 years apart, it was most likely buried as a consequence of the Viking attack on Northumbria and fall of the city of York in 866.
The hoard was discovered in March 1847 by William Foster a laborer working in a field alongside the banks of the river Wharfe, between the villages of Ulleskelf and Bolton Percy, a little over 10 miles from the city of York. The field in question had been disturbed by drainage work in the fall of 1846, the scattered hoard being ploughed out in the following spring. The coins, bronze stycas, several thousand in number were compacted with verdigris into a mass and rapidly dispersed by the finders on discovery; later examination of the site by William Fennell brought to light more stray coins and traces of a leather container in which the hoard had been deposited. Fennell only managed to record a small parcel from the hoard in the 1849 Journal of the British Archaeological Association."