Final answer:
Athena is the goddess associated with a helmet and spear, symbolizing her roles in warfare and wisdom as seen in historical artistic depictions like the Athena Promachos statue.
Step-by-step explanation:
The god or goddess associated with a helmet and spear is Athena. She is recognized as the goddess of warfare and wisdom. The imagery of Athena often includes a helmet and spear, symbolizing her martial prowess and strategic intellect. This association is confirmed by historical accounts and artistic representations, including the colossal bronze statue of Athena Promachos at the Acropolis. This statue featured Athena with a helmet, shield, and spear, signifying her readiness for battle.