Complex sentence: In 1913 Kičevo and the whole region were incorporated in the Kingdom of Serbia, and as such, became part of the Kingdom of Serbs, Croats and Slovenes in 1918.
Split into simpler sentences: In 1913 Kičevo and the whole region were incorporated in the Kingdom of Serbia. It became part of the Kingdom of Serbs, Croats and Slovenes in 1918.