Copper and tin were amalgamated in clay crucibles and then cast into pottery or stone moulds. Bronze was cast in two different ways. The first involved the use of stone bivalve moulds which could be re-used many times, whilst the second method, known as the lost wax technique, used clay moulds. In the lost wax technique the required object (bracelets, armlets and necklaces) is first modelled in wax, and then packed in clay and fired. The wax melts, escaping through an opening left in the clay shell, leaving a permanent impression in the fired pottery mould. Molten metal is then poured in through the same opening. The mould has to be broken in order to remove the cast metal object and can be used only once. Many items made in moulds required further processing to remove casting seams or to emphasize incised decoration. Seams and irregularities in the surface were probably smoothed using whetstones, whilst detailed finishing was carried out using bronze tools with a narrow chisel-like blade.
Funerary monuments indicated differences in social status. Large barrows (earthen mounds) were raised over stone burial chambers. Known as ‘princely graves’, these tombs were probably reserved for elite members of society. The best known examples of this type of grave include the four barrows from Łęki Małe, Kościan District, which survive in situ to this day, and the barrow from Grabonóg, Gostyń District, presented in this exhibition.
The importance of the individuals buried in barrows is further demonstrated by the grave goods interred with them, in particular so-called dagger-sceptres which are considered to be a symbol of power (finds of this sort have been recovered from graves at cemetery site in Łęki Małe), and daggers.
The hoard of copper artefacts from Bytyń (Szamotuły district) is the only discovery of its kind in Poland. It was found by chance in 1873 by a group of labourers who were trying to break up a boulder lying in a local field. At a depth of c. 70 cm beneath this rock they found a figurine of a pair of oxen and six flat axe-heads, four of which can be seen at our exhibition.
The majority of bronze artefacts found in Greater Poland come from collections of objects known as hoards. These consist of weapons, tools and personal decorations. The hoards from Granowo, district of Grodzisk Wlkp. and Poniec, district of Gostyń presented in this exhibition, are among the most valuable discovered in this region.