All of the mentioned people are a part of ancient Greece
Leonidas- He was the king of Sparta, a city located in ancient Greece
Philip of Macedon- He was the king of Macedon (ancient Greece) who has its origin from the Argead dynasty
Alexander the Great- Also known as Alexander III he is a popular king known for his conquests around the world.
Cleisthenes- He is a Greek lawmaker who is known for creating the constitution of ancient Greece
Solon- A Greek lawmaker who is known for laying the foundation stone for Greek democracy
Demosthenes- An orator from ancient Greece. He is also known for his statesmanship