On May 23, 1701, Captain William Kidd met his fate on the banks of the Thames River in London, leaving behind a controversial legacy and an ongoing search for his buried treasure. His execution was particularly gruesome: The rope broke on the first attempt, forcing the executioner to hang him a second time.

Denounced as a pirate in November 1698, Kidd surrendered himself to authorities, convinced he could prove his innocence. Instead, he was imprisoned in the Massachusetts Bay Colony for nearly a year before he was transported to London for trial. In May 1701, Kidd was convicted of multiple counts of piracy and the murder of a crewman.

Just before he died, Kidd allegedly declared, “I have nothing to say except that I have been sworn against by perjured and wicked people.”

Was he really a pirate? Charlie Beeker, the underwater archaeologist who discovered the wreck of Kidd’s ship, the Quedagh Merchant, in 2007, describes him as “a privateer who got caught up in politics and was hanged as a pirate, but that doesn’t necessarily make him a pirate.”