As the nephew of Lord Salisbury, Arthur Balfour's parliamentary career was not initially taken very seriously. Born in Scotland and first gaining a name for himself through publications in philosophy, he became Conservative MP for Hertford in 1874. He was assumed to be little more than an amateur for some time, but proved himself as Irish Secretary under Salisbury between 1887 and 1891, restoring the rule of law in Ireland in an efficient and even ruthless way, earning the nickname of 'Bloody Balfour'. In 1891, he became Leader of the Conservatives in the House of Commons, since Prime Minister Salisbury held his seat in the House of Lords. When his uncle retired in 1901, Balfour was his natural successor.
Editors. "Arthur Balfour becomes Prime Minister". The Literary Encyclopedia. First published 30 August 2013
[http://www.litencyc.com/php/stopics.php?rec=true&UID=1870, accessed 12 February 2016.]