In 1996 someone found a Viking hoard at Westerklief on the former island of Wieringen, The Netherlands. The treasure contained Carolingian and Arab coins, bracelets and silver ingots, all buried in an earthenware pot. The coins date the treasure at around 850. Wieringen at that time was a part of Frisia.
In 1997 some loose objects like coins and rings were found, in 1999 a second treasure , and in 2001 a third, all on the same tiny island.
The treasure is now on display in the Museum of Antiquities in Leiden.
For more info: pagowirense