John Dudley, Ist Duke of Northumberland, together with William Pembroke, 1st Earl of Pembroke arranged the political match of their children in a plan to secure the succession of Lady Jane Grey and to graft their lineage onto the throne of England. Guildford Dudley married the Lady Jane Grey and Henry Herbert married the 13 year old Lady Catherine Grey on the 25th of May 1553. For Lady Jane and Guilford the plan ended in their execution along with John Dudley. The Pembokes were pardoned.
Lord Guildford Dudley, whose arranged marriage with Lady Jane Grey meant his downfall. They were placed on the throne (due to Jane being in the line of succession) in order to prevent the Catholic Mary I from being crowned. After reigning for 9 days, he and Jane lost their heads at Tower of London. He was only 19.
Miniature of Lady Jane Grey
Detail of a miniature 'of a lady called Lady Jane Grey
This supposedly shows the execution of John Dudley, Duke of Northumberland. He was the father of Robert Dudley (Elizabeth's favourite) and Guildford Dudley. The story is that he forced Guildford to marry Lady Jane Grey, and then rushed to put Jane on the throne when Edward VI died. Mary Tudor (Bloody Mary) was able to raise an army, march on London, capture Northumberland, and have him executed for treason.