The Seleucid army from the east had invaded Roman Protectorate Egypt.
The Roman ambassador (Gaius Popillus Laenas) in Egypt confronts Seleucid King Antiochus IV and demands that Antiochus commit to withdraw from Egypt. The ambassador draws a circle in the sand around Antiochus. The Roman ambassador demands that Antiochus—prior to crossing the circle line in the sand—commit to withdrawing all his forces from Egypt, implying that Antiochus’s breach of the circle in the absence of a commitment to withdraw, would provoke war with Rome. Antiochus hesitates, but then capitulates and commits to withdraw from Egypt. The Roman ambassador shakes his hand and Antiochus exits the circle in the sand. Antiocus subsequently indeed withdraws his forces from Egypt.