Complex sentence: In April 1852 he succeeded his father as 2nd Baron Panmure, and early in 1855 he joined Lord Palmerston's cabinet, filling the new office of Secretary of State for War.
Split into simpler sentences: In April 1852, he succeeded his father as 2nd Baron Panmure. In early 1855, he joined Lord Palmerston's cabinet, filling the new office of Secretary of State for War.