became requisite in all civil business, and a real usefulness in common life was thus superadded to the spiritual sanctity of their character. [FN [a] L'Abbé Conc. tom. x. p. 371, 372. com. 2. [b] Padre Paolo sopra benef. eccles. p. 30.] When the usurpations, therefore, of the church had come to such maturity as to embolden her to attempt extorting the right of investitures from the temporal power, Europe, especially Italy and Germany, was thrown into the most violent convulsions, and the pope and the emperor waged implacable war on each other. Gregory dared to fulminate the sentence of excommunication against Henry and his adherents, to pronounce him rightfully deposed, to free his subjects from their oaths of allegiance; and instead of shocking mankind by this gross encroachment on the civil authority, he found the stupid people ready to second his most exorbitant pretensions. Every minister, servant, or vassal of the emperor, who received any disgust, covered his rebellion under the pretence of principle; and even the mother of this monarch, forgetting all the ties of nature, was seduced to countenance the insolence of his enemies. Princes themselves, not attentive to the pernicious consequences of those papal claims, employed them for their present purposes; and the controversy, spreading into every city of Italy, engendered the parties of Guelf and Ghibbelin; the most durable and most inveterate factions that ever arose from the mixture of ambition and religious zeal. Besides numberless assassinations, tumults, and convulsions to which they gave rise, it is computed that the quarrel occasioned no less than sixty battles in the reign of Henry IV., and eighteen in that of his successor, Henry V., when the claims of the sovereign pontiff finally prevailed [c]. [FN [c] Padre Paolo sopra benef. eccles. p. 113.]