Werner von Urslingen (called in Italian: Guarnieri d'Urslingen or Duca Guarnieri; c. 1308 – 1354) was a mercenary of German-speaking origins in the Holy Roman Empire. He is also known as Werner of Urslingen. Biography Werner was born at Irslingen, in Irslingen Swabia, a member of the family of the dukes of Urslingen, and probably a descendant of the dukes of Spoleto. In 1338 he fought for the Republic of Venice against Mastino II della Scala of Verona. After the end of that conflict he entered the Compagnia di San Giorgio, financed by the Veronese and led by Lodrisio Visconti, and took part in the battle of Parabiago. In 1342 Werner joined the service of the Republic of Pisa in its war against Florence, whose troops were led by Malatesta III Malatesta. After that war he collected a troop of adventurers under the name Great Company, with which he plundered rural Tuscany, Umbria, and the Romagna. He supported Francesco Ordelaffi against the Papal States, and was bribed by his enemy, Malatestino Malatesta of Rimini, to help him in his feud with Ferrantino Malatesta. In 1343 Werner was hired by Taddeo Pepoli of Bologna for a very large sum, to fight against Obizzo III d'Este of Modena; but he switched to the Este side and went on to ravage several cities, including Correggio. His company was subsequently expelled from the Ferrara area, and Werner of Urslingen returned to Germany with some of his men. In 1347 he returned to the Italian peninsula and entered the service of Louis I the Great, king of Hungary and Poland, whom he assisted to obtain possession of Naples. Werner of Urslingen's troops defeated Louis, Prince of Taranto (Joan's husband) near Naples, and King Louis was able to enter the city; the following year, however, Werner was accused of collaboration with Joan, and arrested. After having been freed, he entered the service of the Caetani of Fondi with 3,000 men, to attack the Orsini at Supino. In 1348 he sacked and destroyed Anagni: this spurred Perugia and other communes to muster an army against him, and Werner, whose troops had also been struck by the plague, was forced to retreat. He then joined the service of the Papal States, for which he conquered several territories, and then that of Joan of Naples, whom he helped to return in Naples. In 1349, after a period of fighting