Simplify the following text for a Grade 9 native English-speaking person.
Original: George Hamilton-Gordon , 4th Earl of Aberdeen KG , KT , FRS , PC ( 28 January 1784 â `` 14 December 1860 ) , styled Lord Haddo from 1791 to 1801 , was a Scottish politician , successively a Tory , Conservative and Peelite , who served as Prime Minister of the United Kingdom from 1852 until 1855 .
Simplified: George Hamilton-Gordon , 4th Earl of Aberdeen , KG , KT , PC ( 28 January 1784 â `` 14 December 1860 ) was a Scottish Tory\/Peelite politician . He served as Prime Minister of the United Kingdom from 1852 until 1855 .