Complex sentence: Her paternal grandfather, Conrad Ostberg Stone, was of Swedish descent and his family's original surname "Sten" was anglicized to "Stone" when immigrating to the United States through Ellis Island.
Split into simpler sentences: Her paternal grandfather, Conrad Ostberg Stone, was of Swedish descent. His family's original surname "Sten" was anglicized as "Stone" when they immigrated to the United States through Ellis Island.