Complex sentence: Henry Gerber had lived in Germany, and became familiar with the early German homosexual emancipation movement led by such people as Dr. Magnus Hirschfeld, and sought to create a similar political movement within the United States.
Split into simpler sentences: Henry Gerber had lived in Germany, where he became familiar with the early German homosexual emancipation movement led by such people as Dr. Magnus Hirschfeld. He sought to create a similar political movement within the United States.