One of the top professions in ancient Greece was mercenary soldier. After the Peloponnesian War 10,000 Greek mercenaries from all over Greece famously joined a rebellion in the Persian Empire.
After the second Persian invasion of Greece was halted, Sparta withdrew from the Delian League and reformed the Peloponnesian League with its original allies. Many Greek city-states had been alienated from Sparta following the violent actions of Spartan leader Pausanias during the siege of Byzantium. Following Sparta’s departure from the Delian League, Athens was able to use the resources of the League to its own ends, which led it into conflict with less powerful members of the League. The Persian Empire adopted a divide-and-rule strategy in relation to the Greek city-states in the wake of the Persian Wars, stoking already simmering conflicts, including the rivalry between Athens and Sparta, to protect the Persian Empire against further Greek attacks.
In the 1800s they used steel plows and other new forms of technology. The Steel Plow was used for farming to break up tough soil without soil getting stuck to it.
Answer:The problem was that Charles II did not have an heir. The French wanted Duke Philip to succeed the throne while the Hapsburgs recommended Archduke Charles to the throne. Both sides had firm claims and this would affect the balance of power in the area.