Complex sentence: There is an hypothesis who stated the existence of another daughter of Mieszko I who was married with a Pomeranian Slavic Prince; she could be the daughter of either Dobrawa or one of his previous pagan wives.
Split into simpler sentences: There is an hypothesis asserting the existence of another daughter of Mieszko I who was married to a Pomeranian Slavic Prince. She could have been the daughter of either Dobrawa or one of Mieszko's previous pagan wives.