Dewar's The Monarch 15 Year Old Scotch is a blend of whiskies aged in ex-bourbon and ex-sherry casks, which then undergo a secondary aging to marry the flavors. It's named after the famous (some would say clichéd) Edwin Landseer painting The Monarch of the Glen, an 1851 work that John Dewar and Sons purchased in 1919. It depicts a majestic stag overlooking the Scottish Highlands, an iconic image, if a bit on the nose.
Dewar's was founded by John Dewar, Sr. in 1846, later taken over by his sons, and eventually worked its through the corporate maze to become part of Bacardi. The brand was popularized in two fairly unconventional ways: Tommy Dewar, one of John's sons, was a successful travel journalist who used his platform to promote the family business, and Andrew Carnegie sort-of-famously sent a cask of Dewar's to the White House to celebrate Benjamin Harrison's inauguration in 1889. It has since become one of the best-selling blended scotch whiskies in the world.