About 50 miles south and east of Rome, high in the Apennine mountains, lies the Charterhouse of Trisulti whose isolated magnificence prompted the German historian Ferdinand Gregorovius (who stumbled upon it in the 1850’s) to write in his classic work Years of Wandering in Italy, “If a place exists where the human spirit can reach the gravest and highest meditation, this must be it, in one of the most sublime states of solitude I have ever seen.” Here, in this huge deserted monastery founded in 1204, which has 15,000 square meters of roof, President Donald Trump’s former chief strategist and...