John Frederick, Duke Of Brunswick-Lüneburg

John Frederick (German: Johann Friedrich) was born on 25 April 1625 in Herzberg am Harz and died on 18 December 1679 in Augsburg. He was a member of the House of Welf and held the title of duke of Brunswick-Lüneburg. His rule extended over the Principality of Calenberg, a subdivision of the duchy, beginning in 1665 until his death.

He was the third son of George, Duke of Brunswick-Lüneburg. In 1651, during a visit to Italy, John Frederick converted to the Roman Catholic Church, becoming the only member of his family to do so. The conversion was influenced by a visit to Saint Joseph of Cupertino.

In terms of territorial inheritance, John Frederick received the Principality of Calenberg after his elder brother, George William, inherited the Principality of Lüneburg.

In 1666, John Frederick commissioned the construction of a palace in Herrenhausen near Hanover. The palace’s design was inspired by the Palace of Versailles, and it is renowned for its gardens, known as the Herrenhausen Gardens. In 1667, he engaged Girolamo Sartorio, a Venetian architect, as his master builder. Sartorio contributed to numerous buildings in Herrenhausen, including the Neustädter Kirche, and played a significant role in expanding the gardens.

In 1676, John Frederick appointed Gottfried Wilhelm Leibniz as Privy Councillor and librarian of the ducal library. This appointment marked the beginning of Leibniz’s 40-year association with the House of Hanover, during which Leibniz became one of Europe's most influential philosophers and mathematicians and served three generations of the Hanover family.

John Frederick married Benedicta Henrietta of the Palatinate on 30 November 1668. She was born on 14 March 1652 and died on 12 August 1730. She was the daughter of Edward, Count Palatine of Simmern, and Anna Gonzaga. The couple had four daughters:

- Anna Sophie (10 February 1670 – 24 March 1672), who died in childhood;

- Charlotte Felicitas (8 March 1671 – 29 September 1710), who married Rinaldo d'Este, Duke of Modena;

- Henriette Maria (9 March 1672 – 4 September 1687), who died unmarried;

- Wilhelmina Amalia (1673 – 10 April 1742), who married Joseph I, Holy Roman Emperor.

There is no additional information provided regarding his ancestry beyond the references cited, which include the Allgemeine Deutsche Biographie and the House of Welf site.