The archaeologist Mirosław Andrałojć and electronic engineer Piotr Szyngiera localised in Obra, district of Wolsztyn, a site where one of the most important early medieval hoard ever in Poland was accidentally discovered in 1930 . Sondages conducted 11 June 2005 by discoverers, archaeologist Małgorzata Andrałojć and archaeology students Tomasz Bartoszewski, Adam Budynek and Łukasz Dyczkowski yielded 155 fragments of silver coins - dirhams, German denarii (Bavarian and Saxon) and pieces of silver ornaments, as well. The find in Obra is another result of planned investigation financed by the Ministry of Science and Information Technology, administered by the Archaeology Museum in Poznan, and its director is Andrzej Prinke Ph.D.
       Due to field researches (Kałka family from Obra and Wolsztyn) it was possible to learn in details what were the circumstances of the discovery and the context of the find. Obra deposit (in literature is wrong described as originated from Obra Nowa) is reckoned as one of the most important and interesting early medieval hoards in Poland. It is so-called hack-silver hoard, comprised mostly of coins and ornaments cut (hacked) into pieces. The reason of the cutting is a subject of ongoing discussions among scientists. The hoard was hidden in a vessel covered up by another pot. It was buried after 975 and then, most likely after 1000, unearthed and complemented with some coins and buried back (dating by Agnieszka Felczak, Dorota Malarczyk and Sylwia Małachowska). The archaeologists who made the discovery claim that such hoards are related with Viking warriors that live in Poland and their funeral customs.