Complex sentence: Theodore Roosevelt was at his hunting camp, Tauhaus, on September 14,1901, after summiting Marcy, when he was informed that President William McKinley, who had been shot a week earlier, had taken a serious turn for the worse.
Split into simpler sentences: Theodore Roosevelt was at his hunting camp, Tauhaus, on September 14,1901. After summiting Marcy when he was informed that President William McKinley, who had been shot a week earlier, had taken a serious turn for the worse.