What was John Tyler known for?

It's fair to say that John Tyler's Presidency doesn't exactly stand out as one of the great episodes of American history. Most historians regard Tyler as one of the worst ever occupants of the White House; a survey by C-SPAN in 2017 ranked him 39th out of 43 Presidents.
If Tyler is notable for anything—aside from his fathering no fewer than fifteen children from two marriages—it's that he became the first man to succeed to the office of President due to the death of the incumbent. Tyler became President on April 4, 1841 upon the death of William Henry Harrison, who had been in the White House for all of 31 days. It is widely believed that Harrison succumbed to a fever he'd contracted through failing to wear a hat and overcoat on the cold, wet day of his Inauguration. Whatever the reason for Harrison's untimely demise, his Vice-President John Tyler took over as President and presided over an Administration whose achievements were modest at best.