Henry Percy, 9th Earl of Northumberland, KG was an English nobleman. He was a grandee and one of the wealthiest peers of the court of Elizabeth I. Under James I, Northumberland was a long-term prisoner in the Tower of London, due to the suspicion that he was complicit in the Gunpowder Plot. He is known for the circles he moved in as well as for his own achievements. He acquired the sobriquet The Wizard Earl, from his scientific and alchemical experiments, his passion for cartography, and his large library.

Gerald FitzGerald, 11th Earl of Kildare, also known as the "Wizard Earl", was an Irish peer. He was the son of Gerald FitzGerald, 9th Earl of Kildare and his second wife Elizabeth Grey of the Royal House of Grey.