Christian VII (29 January 1749 – 13 March 1808) was King of Denmark and Norway and Duke of Schleswig and Holstein from 1766 until his death in 1808. He was affected by mental illness and was only nominally king for most of his reign. His royal advisers changed depending on the outcome of power struggles. From 1770 to 1772, his court physician Johann Friedrich Struensee was the de facto ruler of the country and introduced progressive reforms signed into law by the king. Struensee was deposed by a coup in 1772, after which the country was ruled by Christian's stepmother, Queen Dowager Juliane Marie of Brunswick-Wolfenbüttel, his half-brother Hereditary Prince Frederick, and the Danish politician Ove Høegh-Guldberg. From 1784 until Christian VII's death in 1808, Christian's son, later Frederick VI, acted as unofficial prince regent.

Christian was born in the early hours of the morning on 29 January 1749 at Christiansborg Palace, the royal residence in Copenhagen. He was the fourth child and second son of the reigning monarch of Denmark–Norway, King Frederick V, and his first wife Louise of Great Britain. The newborn prince was baptized later the same day in the afternoon by the royal confessor Johannes Bartholomæus Bluhme, and was named after his late grandfather, King Christian VI. His godparents were King Frederick V (his father), Queen Dowager Sophie Magdalene (his paternal grandmother), Princess Louise (his aunt) and Princess Charlotte Amalie (his grand-aunt).

A former heir to the throne, also named Christian, had died in infancy in 1747, and the newborn was thus crown prince from birth; therefore, hopes were high for the future of the new heir apparent. Christoph Willibald Gluck, then conductor of the royal opera troupe, composed the opera La Contesa dei Numi (The contention of the gods), in which the Olympian gods gather at the banks of the Great Belt and discuss who in particular should protect the new prince.

At birth, Christian had two elder sisters, Princess Sophia Magdalena and Princess Wilhelmina Caroline, and the family was joined by another daughter, Princess Louise in 1750. In 1751, almost three years after Christian's birth, his mother Queen Louise died during her sixth pregnancy, aged just 27 years. The following year, his father married Duchess Juliana Maria of Brunswick-Wolfenbüttel, who gave birth to Christian's half-brother, Prince Frederick in 1753.

After the early death of his mother, the prince was largely denied parental affection. His stepmother Queen Juliane Marie showed no interest in him, preferring her biological son Hereditary Prince Frederick. Prone to debauchery and increasingly affected by alcoholism, Christian's father became increasingly indifferent to the shy, sensitive child, who was also prone to epileptic seizures. Nonetheless, early historians state that Christian had a delightful personality and considerable talent, but that he was poorly educated and systematically terrorized, and even flogged, by a brutal tutor, Count Christian Ditlev Frederik Reventlow. He seems to have been intelligent and had periods of clarity, but had severe emotional problems, possibly schizophrenia, as argued by Doctor Viggo Christiansen in Christian VII's mental illness (1906). He masturbated frequently, which worried his court physicians and tutor, who thought the practice reduced the prince's fertility and affected his capacity for learning.

After a long period of infirmity, Frederick V died on 14 January 1766, just 42 years old. At the death of his father, Christian immediately ascended the thrones of Denmark and Norway as their sixth absolute monarch, a few weeks before his 17th birthday. Later the same day, Christian was proclaimed king from the balcony of Christiansborg Palace. Christian's reign was marked by severe mental illness, which affected government decisions, and for most of his reign, Christian was only nominally king. His royal advisers changed depending on who won power struggles around the throne. Bored by the politics of being king, a few years after his accesion to the throne, Christian was given a 9 year old slave boy called Moranti, whom he could play games with. The two would eventually become friends, and the king would spend much of his time with the young boy.

Later the same year, the young king married his first cousin, the 15-year-old Princess Caroline Matilda of Great Britain, in a dynastic marriage. They had been betrothed already in 1765. Her brother, King George III of Great Britain, was anxious about the marriage but not aware that the bridegroom was mentally ill. They were married in a proxy wedding ceremony on 1 October 1766 in the Chapel Royal of St James's Palace in London, with the Princess's brother, Prince Edward, Duke of York and Albany, acting as the representative of the groom. After her arrival in Copenhagen, another wedding ceremony took place on 8 November 1766 in the royal chapel at Christiansborg Palace. Marriage celebrations and balls lasted for another month. On 1 May 1767, Christian VII and Caroline Matilda were crowned King and Queen of Denmark and Norway in the royal chapel of Christiansborg Palace.

The marriage was unhappy, and after his marriage, the king abandoned himself to the worst excesses, especially sexual promiscuity. In 1767, he entered into a relationship with the courtesan Støvlet-Cathrine. He ultimately sank into a condition of mental stupor. Symptoms during this time included paranoia, self-mutilation, and hallucinations. The king showed little interest in the queen and only reluctantly visited her in her chambers. His trusted Swiss tutor, Élie Salomon François Reverdil had to step in, among other things with love letters written in the king's name, in an attempt to make the marriage lead to a pregnancy and thus an heir to the throne. On 28 January 1768, Queen Caroline Mathilde gave birth at Christiansborg Palace to the royal couple's son and heir to throne, the future King Frederick VI.