I did not write this in the form of a Civpedia entry but hopefully it will help:
Demetrios Poliorketes (337-283 BCE) was the son of Antigonos I Monophthalmos (The One-Eyed), the general Alexander left to govern the old Persian satrapy of Phrygia when he marched east to defeat Darius.
Antigonos was one of the Diadochi, or Successors of Alexander, the generals who fought for control of his empire. Demetrios served his father in these wars, and earned his name, which means "The Besieger" when sent with a large fleet to conquer the island of Rhodes in 307 BCE. He besieged the city by land and by sea. This siege has remained famous in military history for the great number of siege engines used, including the Helepolis, a massive siege tower built by Epimachos of Athens, and catapults which were capable of hurling rocks weighing 80 kg a distance of 150 metres. The people of Rhodes defended their city with great courage and determination, and with the help of Ptolemy of Egypt. In the end Demetrios raised the siege and presented them with the siege engines. He engineering efforts are cited by Vitruvius, Eusebius, Plutarch and Diodorus. It was the victory of Rhodes over Demetrios that led to the construction of the famous Colossus.
After the defeat of Antigonos at Ipsos, Demetrios had many adventures, fighting in Greece, Macedon and in Asia, proving himself one of the great generals of his age. He was finally defeated by Seleukos when he invaded Syria in an attempt to rally veterans of his father's armies to his cause, and lived out his life a captive, finally drinking himself to death.
Demetrios' son, Antigonos Gonatas, went on to become king of Macedon and the Antigonid dynasty was one of the three to survive the Successor Wars, along with the Seleukids and Ptolemies, and who continued to rule until absorbed into the expanding Roman state.