1893, Oscar Browning, Guelphs and Ghibellines: A Short History of Mediaeval Italy from 1250-1409, Methuen & Co., page 13, The parties of Guelph and Ghibelline raged as fiercely as if the lances of the German hosts were ever glimmering on the crest of the Alps, or as if the Lombard leagues were in constant watchfulness against an impending foe. […] Speaking generally, the Ghibellines were the party of the emperor, and the Guelphs the party of the Pope; the Ghibellines were on the side of authority, or sometimes of oppression, the Guelphs were on the side of liberty and self-government.
Source: wiktionary