Complex sentence: Stanisław "Cat" Mackiewicz (December 18 1896 in Saint Petersburg-February 18 1966 in Warsaw)-Polish conservative writer, a monarchist, Member of Parliament (Sejm) 1928-1935, from BBWR faction.
Split into simpler sentences: Stanisław "Cat" Mackiewicz (December 18 1896 in Saint Petersburg-February 18 1966 in Warsaw) was a Polish Conservative writer and monarchist. He was a Member of Parliament (Sejm) 1928-1935 representing the BBWR faction.