The Princes of Ottajano (or Ottaiano) are a cadet branch of the ducal dynasty of Tuscany. Along with the Veronese Medici Counts of Caprara, and Gavardo, they make up the last and closest descendants to the main line of the House of Medici.
The founder of the Ottajano line was Ottaviano de' Medici, who married Bartholomea Giugni and gave issue to Bernardetto and Constance, Countess of Donoratico. Bernardetto married Giulia de' Medici, daughter of Alessandro de' Medici, Duke of Florence, descended from Cosimo il Vecchio and Lorenzo the Magnificent of the Medici family's senior line. It was Bernardetto who bought from Gonzaga in 1567 the fiefdom of Ottaiano, located near Naples.
Over the centuries, this remaining House of Medici has reached a leading position in the aristocracy of the Kingdom of Two Sicilies. Among the members of the dynasty are leaders of the Roman Catholic Church, ambassadors, cardinals (Francesco de' Medici Ottaiano), a pope, and Don Luigi de' Medici, representative of the Kingdom of Naples at the Congress of Vienna.
In his book "The History of My Dynasty," Ottaviano de' Medici points to Vatican law at the time and claims that either the Medici Princes of Ottaiano or the Veronese Medici should have inherited the Grand Duchy of Tuscany upon the death of last of the Medici Grand Dukes, Gian Gastone de' Medici, instead of the Habsburg-Lorraine line, since both Medici branches were closer descendants than Francis Stephen of Lorraine (Francis I, Holy Roman Emperor), who was a great-great-great-grandson of Francesco I de' Medici via the female line. However, due to the Habsburg-Lorraine influence, they were able to secure Florence for themselves.