The tribunes of the plebs had the power to convene the "concilium plebis", or plebeian assembly, and propose legislation before it. Only one of the tribunes could preside over this assembly, which had the power to pass laws affecting only the plebeians, known as "plebiscita", or plebiscites. After 287 BC, the decrees of the "concilium plebis" had the effect of law over all Roman citizens. By the 3rd century BC, the tribunes could also convene and propose legislation before the senate.