To shake things up a little I thought I might veer away from the world of art and discuss the fascinating world of forging documents. In this particular case, poetry.
In the mid-eighteenth century, a young Scottish poet by the name of James Macpherson published several rounds of poetry translated from the Gaelic language, the most famous of these being the Works of Ossian, which were published in 1765. The story goes that Macpherson found archaic fragments of works by the long-lost Gaelic poet Ossian, and was encouraged by his editor to translate them into English. The poems were incredibly popular, and arguably was the impetus for the Romantic movement in literature.
Unfortunately, the poems, and even Ossian, were fakes, inventions of Macpherson’s imagination to add legitimacy to his poetic style. The poems have been hotly contested and debated pretty much since their publication, and to this day one can’t really be sure where Macpherson got his sources from. The standard conclusion is that he based his poetry of of Scots-Irish ballads he picked up and transcribed, with a healthy dash of his own imaginative flourishes.