Marie Sophie Friederike of Hesse-Kassel was born on 28 October 1767, in Hanau. She was the daughter of Princess Louise of Denmark and Norway (30 January 1750 - 12 January 1831) and Charles, Landgrave of Hesse-Kassel. Her maternal grandparents were Louise of Great Britain, Queen Consort of Denmark and Norway (7 December 1724 - 19 December 1751) and Frederick V, King of Denmark and Norway (31 March 1723 - 13 January 1766). Her paternal grandparents were Princess Mary of Great Britain and Frederick II of Hesse-Kassel. Marie Sophie's parents were married on 30 August 1766, at Christiansborg Slot, in Copenhagen. Her siblings were: Prince Wilhelm of Hesse-Kassel (15 January 1769 - 14 July 1772), Prince Frederik of Hesse-Kassel (24 May 1771 - 24 February 1845), Princess Juliane of Hesse-Kassel (19 January 1773 - 11 March 1860), Prince Christian of Hesse-Kassel (14 August 1776 - 14 November 1814) and Princess Louise Caroline of Hesse-Kassel (28 September 1789 - 13 March 1867). Marie Sophie of Hesse-Kassel married Crown Prince Frederick of Denmark (28 January 1768 - 3 December 1839) on 31 July 1790, in Gottorp. He was the son of Caroline Matilda of Great Britain, Queen Consort of Denmark and Norway (11 July 1751 - 10 May 1775) and Christian VII, King of Denmark and Norway (29 January 1749 - 13 March 1808). The couple had eight children.
The Children of Marie Sophie of Hesse-Kassel and Frederick VI:
Prince Christian of Denmark (22 September 1791 - 23 September 1791)
Princess Marie Louise of Denmark (19 November 1792 - 12 October 1793)
Princess Caroline of Denmark (28 October 1793 - 30 March 1881) Married Frederick Ferdinand of Denmark.
Princess Louise of Denmark (21 August 1795 - 7 December 1795)
Prince Christian of Denmark (1 September 1797 - 5 September 1797)
Princess Juliana Louise of Denmark (12 February 1802 - 23 February 1802)
Princess Frederikke Marie of Denmark (3 June 1805 - 14 July 1805)
Princess Wilhelmine of Denmark (18 January 1808 - 30 May 1891) Married 1st: Prince Frederick of Denmark in 1828. Married 2nd: Karl, Duke of Schleswig-Holstein-Sonderburg-Glücksburg in 1838.
Her father-in-law, Christian VII died on 13 March 1808, in Rendsburg. He was interred in Roskilde Cathedral. He was succeeded by her husband, as Frederick VI. Frederick VI died on 3 December 1839, at Amalienborg Palace, in Copenhagen. He was succeeded by his cousin, as Christian VIII. Marie Sophie of Hesse-Kassel died aged 84, on 22 March 1852, at Frederiksberg Palace. She was interred in Roskilde Cathedral.