In 1603, English officials arrested Sir Walter Raleigh. They charged him with treason. He was allegedly involved in a plot to overthrow and kill the new King, James I.

At his trial, prosecutors entered just one piece of evidence. It was a confession letter written by the man who allegedly planned the plot, Lord Cobham. The letter named Raleigh a co-conspirator.

Sir Walter Raleigh said the confession alone was not reliable. If he could bring Cobham to testify in court, he would at least have a chance to cross-examine the only witness against him.

But the English courts at the time were not particularly interested in due process. They convicted Raleigh without allowing him to confront or examine the witness.

He was imprisoned, and eventually executed.

Fast forward to USA, 2017. A man faces murder charges. And the main witness against him is a computer algorithm.