Sir John Herbert (1550 – 9 July 1617) was a Welsh lawyer, diplomat and politician who sat in the House of Commons at various times between 1586 and 1611.
Herbert was a talented linguist (not just speaking English and Welsh) and so was used to interrogate foreign prisoners and on trade and political missions to Denmark, Poland, Brandenburg, the Netherlands and France.
When Robert Cecil, 1st Earl of Salisbury died in 1612, Herbert hoped to succeed him as principal secretary of state, but James I left the office vacant until 1614.
He died in Cardiff aged 67 on 9 July 1617, having fought a duel with Sir Lewis Tresham two months earlier.
Cecil and Herbert lodged at a house of the Duke of Montpensier in Paris, and subsequently travelled south to meet Henry IV of France at Angers in March.
They sailed home to Portsmouth from Ouistreham, a port near Caen, in the Adventure commanded by Sir Alexander Clifford.