TripAdvisor currently ranks the Baron Hotel fourth among the nineteen establishments it mentions in Aleppo. In reality, the city’s most venerable hotel has been shuttered since the Syrian civil war erupted in 2011, though intrepid visitors who brave the dangers outside and enter its cool, faded vestibule can still see T.E. Lawrence’s hotel bill and admire the desk where Agatha Christie once worked on Murder on the Orient Express.

The brothers Onnig and Armenak Mazloumian, who founded the hotel before World War I, were convivial and enterprising Aleppans, part of an Armenian community whose presence in the Syrian city went back many centuries. They were known locally as “the barons” after their establishment, which played much the same part in the life of the region as Shepheard’s did in Cairo, the Grande Bretagne in Athens, and the Pera Palace in Istanbul. Its wood-paneled dining room, tiled floors, and well-stocked bar attracted European visitors before and after World War I. During the war the visits ceased, and it became the preferred watering hole of the city’s most senior Ottoman civilian and military officials, including Cemal Pasha, the governor of Syria and one of the most powerful figures in the wartime government, who became the brothers’ protector.

They certainly needed him. By the time Cemal Pasha arrived in the region, enormous numbers of Armenians were being massacred across the eastern provinces of the Ottoman Empire, and hundreds of thousands more were being deported and sent to die in rudimentary camps in the Syrian deserts to the city’s east. Aleppo itself quickly filled up with refugees testifying to the horrors they had witnessed. Initially, the brothers and other notables were allowed to organize humanitarian assistance for the deportees, but even after official policy became harsher and the Ottomans began to deport the community’s leaders, the Mazloumians continued to provide clandestine support for their fellow Armenians, using their contacts with local officials.

In late October 1918, four centuries of Ottoman rule in Syria ended. Turkish troops retreated under the command of Mustafa Kemal—later the founder of the republic of Turkey (and better known as Atatürk)—and were pursued by the emir Faisal’s Arab forces, by Mysore lancers, and by Australian armored car units. It was in these confused weeks that the Baron Hotel witnessed the last and perhaps the most remarkable Ottoman–Armenian exchange of all. Among those who had survived the massacres was a prominent journalist from Istanbul named Aram Andonian, who had been arrested in the first Istanbul round-up of notables in April 1915 and sent into the Syrian desert. He managed to escape, making his way back to the relative safety of Aleppo.

He had been able to do this thanks largely to a minor Ottoman official named Naim Bey,…