The early years of the Republic were a time of external strife and periodic popular unrest. In 494 BC, under harsh measures from patrician creditors, during a military campaign, the plebeians under arms seceded to the Mons Sacer outside the city and refused to fight in the campaign without political concessions. With the pressure of an external threat, the patricians were forced to recognise the office of Plebeian tribune () who were declared sacrosanct, i.e. that they were declared inviolable and that anyone could be summarily executed for violation of the sanctity of his person. This was the basis of the tribune's ability to veto (literally translated as "I forbid") any political act or to protect any individual from an injustice committed by a magistrate, known as "intercessio" and "auxilium", respectively. The people gave the tribunes, whose number is unclear, two assistants known as plebeian aediles.