Cosimo III de' Medici, Grand Duke of Tuscany
Eleonora Luisa Gonzaga married Francesco Maria de' Medici, Duke of Rovere and Montefeltro (titles inherited from his mother) on 14 July 1709. Her husband was 48 years old and morbidly obese. Before the marriage occurred, Cosimo III de' Medici, Grand Duke of Tuscany, who instigated the marriage, sent agents to Guastalla to ascertain her physical appearance. They concluded that she had beautiful skin, eyes, mouth, and waist. The House of Medici was desperately wanting in male heirs; Francesco Maria, previously a cardinal, was released from his vows through his brother's action to remedy this.