Final answer:
Regulus met the Roman Senate to seek their support and advocacy during a trial in which he was the defendant.
Step-by-step explanation:
Regulus met the Roman Senate because he came to seek their support and advocacy during a trial in which he was the defendant. The Senate, as the governing body of Rome, held significant power and influence. By securing the support of prominent senators, Regulus hoped to sway public opinion and improve his chances of a favorable outcome in his case.