Richard Cromwell
4 Oktober 1626-12 July 1712. Son of "Lord Protector" Oliver Cromwell. He followed in his father's footsteps as Lord Protector of England, Scotland and Ireland in 1658, but only held this position until 1659.
Since his two older brothers had died early, Richard was nominated "Lord Protector" after his father's death. However, he lacked the experience and the will to maintain this position. He dropped his office and went into exile. This might have lead to a possible 'power vacuum' in the population, with no one to lead the country. So shortly after, Charles II was restored to the throne.
Sources
http://www.british-civil-wars.co.uk/biog/richard-cromwell.htm