He wrote the last quartets amidst failing health. In April 1825 he was bedridden and remained ill for about a month. The illness—or more precisely, his recovery from it—is remembered for having given rise to the deeply felt slow movement of the Fifteenth Quartet, which he called "Holy song of thanks ('Heiliger Dankgesang') to the divinity, from one, made well." He went on to complete the quartets now numbered Thirteenth, Fourteenth, and Sixteenth. The last work completed by Beethoven was the substitute final movement of the Thirteenth Quartet, which replaced the difficult Große Fuge. Shortly thereafter, in December 1826, illness struck again, with episodes of vomiting and diarrhea that nearly ended his life.
The 1825 Miramichi fire, or Great Miramichi Fire, or Great Fire of Miramichi, as it came to be known, was a massive forest fire complex that devastated forests and communities throughout much of northern New Brunswick in October 1825. It ranks among the three largest forest fires ever recorded in North America. About 160 people died in and around Newcastle, including prisoners in the Newcastle Jail. Elsewhere, the totals were likely higher, given the number of lumbermen in the forests at the time (about 3000). To escape the blaze many residents took refuge with livestock and wildlife in the Miramichi River.