I want to know the answer to the following question:
When did Demetrius seize the Macedonian throne?
All the background I'm provided with is that "Seleucus then attempted to conquer Lysimachus' European territories in Thrace and Macedon, but he was assassinated by Ptolemy Ceraunus ("the thunderbolt"), who had taken refuge at the Seleucid court and then had himself acclaimed as king of Macedon.". Is that enough to answer the question?