Complex sentence: Astrid was born to King Olof Skötkonung of Sweden and his Obotritian mistress Edla, half sister of King Anund Jacob of Sweden and sister of King Emund the Old of Sweden.
Split into simpler sentences: Astrid was born to King Olof Skötkonung of Sweden and his Obotritian mistress Edla. She was the half sister of King Anund Jacob of Sweden and sister of King Emund the Old of Sweden.