Among the artifacts from the Iron Age, glass beads are important evidence. Different kinds of glass beads recovered from several sites across Cambodia, such as the Phum Snay site in the northwest and the Prohear site in the southeast, show that there were two main trading networks at the time. The two networks were separated by time and space, which indicate that there was a shift from one network to the other at about 2nd–4th century AD, probably with changes in socio-political powers.