The so-called Battle of Crocus Field was a battle in the Third Sacred War, fought between the armies of Phocis, under Onomarchos, and the combined Thessalian and Macedonian army under Philip II of Macedon. The Phocians were decisively defeated by Philip's forces. Philip's victory secured his appointment as ruler of Thessaly, marking an important step in the rise of Macedon to political ascendancy in Ancient Greece. Opinion amongst historians is divided as to the year of the battle; some favour 353 BC, and others 352 BC.

The Third Sacred War was fought between the forces of the Delphic Amphictyonic League, principally represented by Thebes, and latterly by Philip II of Macedon, and the Phocians. The war was caused by a large fine imposed in 357 BC on the Phocians by the Amphictyonic League, for the offense of cultivating sacred land; refusing to pay, the Phocians instead seized the Temple of Apollo in Delphi, and used the accumulated treasures to fund large mercenary armies. Thus, although the Phocians suffered several major defeats, they were able to continue the war for many years, until eventually all parties were nearing exhaustion. Philip II used the distraction of the other states to increase his power in northern Greece, in the process becoming ruler of Thessaly. In the end, Philip's growing power, and the exhaustion of the other states, allowed him to impose a peaceful settlement of the war, marking a major step in the rise of Macedon to pre-eminence in Ancient Greece.