"Philadelphia" comes from the Greek "loving" (phil) "brother" (delphos) or figuratively "loving the brethren." The founder of the Pennsylvania town, William Penn, was a Quaker who experienced persecution and wanted to name his town for a mindset of religious acceptance. There's also a pharaoh named Ptolemy II Philadelphus (285-46 B.C.), called because he married his sister Arsinoe II. Therefore, he is a "loving brother" for his sister. So there's that too to think about whenever you travel to Philadelphia.