Final answer:
Alexander III, later known as Alexander the Great, succeeded Philip II of Macedon on the throne after his father's assassination in 336 BCE.
Step-by-step explanation:
After the assassination of Philip II of Macedon in 336 BCE, his son Alexander III, who is commonly known as Alexander the Great, ascended to the throne at the age of twenty. Alexander proved to be a formidable leader, immediately facing and overcoming challenges such as the invasion by Thracian tribes and a rebellion in Greece. He continued his father's mission to expand Macedonian power by engaging in a campaign against Persia, winning significant battles such as those at Issus and Gaugamela, and eventually asserting control over the Persian Empire.