Despite the birth of Mary's son James who was born on 19 June 1566 in Edinburgh Castle, the relationship between Mary and Darnley deteriorated. The young Darnley spent the evenings out drinking and womanising.
On 9 February 1567, Darnley had become unwell – perhaps with smallpox - and went to stay in the Provost’s lodgings at Kirk o’ Field in Edinburgh.
Mary had visited Darnley on the day of his death, but left to attend a masque in Holyrood to celebrate the marriage of one of her ladies in waiting.
At two o’clock in the morning there was a massive explosion at Kirk o’ Field which was felt throughout the city.
Darnley’s body was found in a neighbouring garden the next morning, beside that of a servant. It seemed that they had run from the house in their nightwear and in terror.
They did not appear to have been victims of an explosion, but had been strangled. The Queen’s husband had been murdered. He was 21 years old.