Complex sentence: At one point in the 970s, Mieszko I of Poland apparently took over the region: the "Primary Chronicle" infers this when reporting that Vladimir I of Kiev conquered the "Cherven towns" from the Poles in 981.
Split into simpler sentences: At one point in the 970s, the region seems to have been taken over by Mieszko I of Poland. This may be inferred from the Primary Chronicle which reports that Vladimir I of Kiev conquered the "Cherven towns" from the Poles in 981.