Complex sentence: When the Turks sued for peace, and concluded an armistice on the 3rd of December 1912 with the Serbians and Bulgarians, the Powers decided to arrange a peace conference in London, known as the St. James Conference, and invited the belligerents to participate.
Split into simpler sentences: When the Turks sued for peace, and concluded an armistice on the 3rd of December 1912 with the Serbians and Bulgarians. The Powers arranged a peace conference in London, known as the St. James Conference, and invited the belligerents to participate.