nd 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.]

But the bold spirit of Gregory, not dismayed with the vigorous
opposition which he met with from the emperor, extended his
usurpations all over Europe; and well knowing the nature of mankind,
whose blind astonishment ever inclines them to yield to the most
impudent pretensions, he seemed determined to set no bounds to the
spiritual, or rather temporal monarchy, which he had undertaken to
erect. He pronounced the sentence of excommunication against
Nicephorus, Emperor of the East: Robert Guiscard, the adventurous
Norman, who had acquired the dominion of Naples, was attacked by the
same dangerous weapon: he degraded Boleslas, King of Poland, from the
rank of king; and even deprived Poland of the title of a kingdom: he
attempted to treat Philip, King of France, with the same rigour which
he had employed against the emperor [d]: he pretended to the entire
property and dominion of Spain; and he parcelled it out amongst
adventurers, who undertook to conquer it from the Saracens, and to
hold it in vassalage under the see of Rome [e]: even the Christian
bishops, on whose aid he relied for subduing the temporal princes, saw
that he was determined to reduce them to servitude; and by assuming
the whole legislative and judicial power of the church, to centre all
authority in the sovereign pontiff [f].
[FN [d] Epist. Greg. VII. epist. 32, 35. lib. 2. epist. 5. [e] Epist.
Greg. VII. lib. 1. epist. 7. [f] Greg. epist. lib. 2. epist. 55.]

William the Conqueror, the most potent, the most haughty, and the most
vigorous prince in Europe, was not, amidst all his splendid successes,
secure from the attacks of this enterprising pontiff. Gregory wrote
him a letter, requiring him to fulfil his promise in doing homage for
the kingdom of England to the see of Rome, and to send him over that
tribute, which all his predecessors had been accustomed to pay to the
vicar of Christ. By the tri