Why did the roman kingdom become a republic

It all began when the Romans overthrew their Etruscan conquerors in 509 B.C.E. Centered north of Rome, the Etruscans had ruled over the Romans for hundreds of years. Once free, the Romans established a republic, a government in which citizens elected representatives to rule on their behalf.

Ithink the answer is discovery verbs because they are quite similar to the verb 'discovering'

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