James Boswell died in 1795 believing he had touched and kissed a cache of Shakespeare's original letters and papers discovered by a Mr. Ireland. His friend, Edmond Malone, publicly exposed the lot as a forgery just a year later.
Lord Macauley's Habit of Exaggeration
In his 1878 book Boswell Again, author T. Davis wrote the following about Lord Thomas Macaulay, the one person who had probably done the most damage to Boswell's personal reputation as a result of comments made in a review of Croker's annotated edition of Life of Johnson (1831):
All who are acquainted with the writings of Lord Macaulay, must be aware that he is more distinguished by skill than candour. He certainly shows the dexterity of an advocate, but not the impartiality of a critic; and for special pleading, Westminster Hall could scarcely produce his equal. He shows a great inclination to exaggerate facts. His geese are all swans. For instance, Boswell relates that on one occasion he "observed that Johnson poured a quantity of wine into a glass and swallowed it greedily." Macaulay says, that "when he drank wine, he drank it greedily, and in large tumblers." As if it had been his habit to do so. Boswell says that "Johnson ate voraciously." But this is too prosaic for his Lordship, who embellishes it thus: "He tore his dinner like a famished wolf." Johnson merely records in his diary, "On Good Friday I took in the afternoon some coffee and buttered bun." Macaulay tells us, "He has gravely noted down that he once committed the sin of drinking coffee on Good Friday." Boswell had a few nicknames. But Macaulay says, "He was always earning some ridiculous nickname, and then binding it as a crown upon him." Johnson had three, or at the most four, persons under his roof, some of whom were neither old nor wretched. Macaulay says, "He turned his house into a place of refuge for a crowd of wretched old creatures." The attentive reader of his works wil detect many other flagrant examples of a like character."
Source: Davis, T. (1878). Boswell again. Reeves & Turner / Philalethes.