Cardenio
From Tardis Wiki, the free Doctor Who reference
Cardenio was a play by William Shakespeare and John Fletcher, believed lost in the 20th century.
Cardenio was one of Shakespeare's more obscure plays. The last known copy was owned by Thomas Sheridan. In 1765, Jack Harkness stole the copy from Thomas. He hid it in a locker at King's Cross, just in case he needed it. After he was trapped in the past and started working for Torchwood Three, he tried to sell it to Hugo Faulkner in 1967. (PROSE: Trace Memory)
