Complex sentence: Stewart Duckworth Headlam (1847--November 18,1924) was an English clergyman, continually involved in controversy in the final decades of the nineteenth century, and considered a pioneer and publicist of Christian socialism, on which he wrote a pamphlet for the Fabian Society.
Split into simpler sentences: Stewart Duckworth Headlam (1847--November 18,1924) was a priest of the Church of England who was involved in frequent controversy in the final decades of the nineteenth century. Headlam was considered a pioneer and publicist of Christian socialism, on which he wrote a pamphlet for the Fabian Society.