Oldcastle's Revolt (1414):-
Sir John Oldcastle (born about 1378 - died 1417) was a popular figure, a friend to Prince Henry (later Henry V) and a valuable leader in Henry IV's campaigns against the Welsh. Oldcastle is presumed to be the model for Shakespeare's Falstaff. It would seem that Oldcastle had all the makings of a long career at court.
But Oldcastle was a firm follower of the teachings of John Wycliffe, and his beliefs brought him into conflict with his king. In 1413 Oldcastle was accused of heresy for his Lollard convictions. He was brought to trial under the influence of Archbishop Arundel, but he refused to recant his beliefs. He was sentenced to death as a heretic, but the sentence was stayed by Henry V, who must have hoped he could convince his friend to recant. Oldcastle was imprisoned in the Tower of London, but he escaped, possibly with the aide of the king. But Oldcastle turned against his friend and began plotting to overthrow the monarchy, seize or kill the king and his brothers, and introduce sweeping religious and social reforms according to his Lollard beliefs.
Unfortunately, Oldcastle's Revolt (1414) was poorly organized, and it lacked any real support from influential nobles who might have been tempted to the Lollard cause. The plan was that a small number of men would enter Eltham Palace in disguise and seize the king. At the same time a second force of men would take London. A gathering of conspirators was set for St Giles Fields, in London. However, the number of men who assembled proved disappointingly small; somewhere between three hundred and one thousand in number.