Ercole I d'Este (26 October 1431 – 15 June 1505) was Duke of Ferrara from 1471 until 1505. He was a member of the House of Este. He was nicknamed North Wind and the Diamond.
Ercole was born at Ferrara to Nicolò III and Ricciarda da Saluzzo. His maternal grandparents were Thomas III of Saluzzo and Marguerite of Roussy.
He was educated at the Neapolitan court of Alfonso, king of Aragon and Naples, from 1445 to 1460; there he studied military arts, chivalry, and acquired the appreciation for architecture all'antica and the fine arts, which would result in his becoming one of the most significant art patrons of the Renaissance.
In 1471, with the support of the Republic of Venice, he became Duke on the death of his half-brother Borso, profiting of the absence of the latter's son, Niccolò, who was in Mantua. During an absence of Ercole from Ferrara, Niccolò attempted a coup, which was however crushed; Niccolò and his cousin Azzo were beheaded on September 4, 1476. Ercole married Eleonora d'Aragona, daughter of Ferdinand I of Naples, in 1473. The Este alliance with Naples was to prove a powerful one.
The House of Este ([ˈɛste] Italian: Casa d'Este, originally House of Welf-Este) is a European princely dynasty. It is one of the most ancient noble dynasties in Europe.
The elder branch of the House of Este included the dukes of Brunswick and Lüneburg (1208–1918) and produced Britain's Hanoverian monarchs and one Emperor of Russia (Ivan VI).
The younger branch of the House of Este included rulers of Ferrara (1240–1597), and Modena and Reggio (1288–1796).
Edward Gibbon said the family originated from the Roman Attii family, which migrated from Rome to Este to defend Italy against the Ostrogoths. However, there is little evidence to support this hypothesis. The names of the early members of the family indicate that a Frankish origin is much more likely. The first known member of the house was Margrave Adalbert of Mainz, known only as father of Oberto I, Count palatine of Italy, who died around 975. Oberto's grandson, Albert Azzo II, Margrave of Milan (996–1097) built a castle at Este, near Padua, and named himself after it. He had three sons from two marriages, two of whom became the ancestors of the two branches of the family: