Complex sentence: In August 1777, as General William Howe began his campaign to capture Philadelphia, American soldiers arrived at Penn's Lansdowne estate near Philadelphia and demanded that he sign a parole stating that he would do nothing to harm the revolutionary cause.
Split into simpler sentences: In August 1777, as General William Howe began his campaign to capture Philadelphia, Patriot soldiers arrived at Penn's Lansdowne estate near Philadelphia. They demanded that he sign a parole stating that he would do nothing to harm the revolutionary cause.