The years after the truce were eventful ones in Greek politics. The Peace of Callias, if it existed, was concluded in 449 BC. It was probably in that same year that Pericles passed the Congress decree, calling for a pan-Hellenic congress to discuss the future of Greece. Modern scholars have debated extensively over the intent of that proposal; some regard it as a good faith effort to secure a lasting peace, while others view it as a propaganda tool. In any event, Sparta derailed the congress by refusing to attend.