He backed up this terrible indictment by a round attack upon the clergy, its general corruption and its practices of simony; and as a result he fell into the hands of the Inquisition.

There it might have gone very ill with him but that King Alfonso rescued him from the clutches of that dread priestly tribunal.
Meanwhile, he had fired his petard.

If a pretext had been wanting to warrant the taking up of arms against the Papacy, that pretext Valla had afforded.

Never was the temporal power of the Church in such danger, and ultimately it must inevitably have succumbed but for the coming of so strong and unscrupulous a man as Sixtus IV to stamp out the patrician factions that were heading the hostile movement.
His election, it is generally admitted, was simoniacal; and by simony he raised the funds necessary for his campaign to reestablish and support the papal authority.

This simony of his, says Dr.Jacob Burckhardt, "grew to unheard-of proportions, and extended from the appointment of cardinals down to the sale of the smallest benefice." Had he employed these means of raising funds for none but the purpose of putting down the assailants of the Pontificate, a measure of justification (political if not ecclesiastical) might be argued in his favour.