Complex sentence: During the week-long celebration following successful negotiations, Lithuanian nobles proclaimed Vytautas as King of Lithuania; while such declaration had no political force, it was a reply to demands by Jadwiga of Poland to pay Polish taxes.
Split into simpler sentences: During the week-long celebration following successful negotiations, Lithuanian nobles proclaimed Vytautas as King of Lithuania. While such a declaration had no political force, it was a reply to demands by Jadwiga of Poland to pay Polish taxes.