1. Antigonus I was a prominent figure in Greek history, known for his role in the Wars of the Diadochi following the death of Alexander the Great.
2. He was one of the most successful of Alexander's generals, eventually becoming the ruler of a large portion of the former empire.
3. Antigonus I played a key role in shaping the political landscape of the Hellenistic world, engaging in numerous military campaigns and diplomatic maneuverings.
4. His style of governance and warfare influenced later Greek leaders and established many of the political and military norms of the time.
5. Antigonus I's presence at a Greek convention would provide valuable insights into the political and military strategies of the Hellenistic period.
6. He would be a key figure to discuss topics related to the legacy of Alexander the Great and the subsequent power struggles among his former generals.
7. Antigonus I's contributions to the Greek world and his impact on later history make him a relevant and important figure to include in any gathering of Greek leaders and historical figures.