“You are a civil engineer, then? My brother was an army engineer,” I said, delighted by the coincidence.

“An engineer?” He laughed, but kindly. “I’m afraid I have no head for such things. No, Agnes, I was—let us say—an observer. I reported on progress to my superiors. There was a considerable investment of money. Many important people were interested in the project.”

Toward noon we circled back toward an impressive square, which was, Karl told me, the very heart of Cairo. There, all the colors of humanity were in evidence. “Sudanese,” Karl whispered, indicating a family so dark as to be nearly purple. As we strolled, he nodded toward Greeks and Italians, Jews and Armenians, Syrians and Lebanese and Cypriots: all sallow and hirsute in varying degrees. “But look there!” Karl said quietly. A slim, square-shouldered youth passed by, slender brown limbs moving with fluid grace beneath his homespun cotton robe. “That is the true Egyptian, Agnes, just as he is depicted on the walls of ancient tombs.”

Together we gazed at the young man’s beauty until Karl was distracted from it by a pair of white-skinned men. “Turko-Circassians,” Karl said. “They ruled Egypt until recently but were displaced by the French and then the British. Which reminds me! Was that not the famous Colonel Lawrence I saw with you yesterday? How do you know him, Agnes?”

I spoke of my sister’s connection and then of Mr. Thomas’s presentation. Karl smiled knowingly. “The world’s most famous spy, our Lawrence—barring only Mata Hari, I should say. They both enjoyed dressing up as Orientals.”

“I’m sorry, Herr—Karl. No, I don’t believe you have the right man. Colonel Lawrence is a British army officer.”

“Among other things.” Karl smiled. “I have followed his career for many years, Agnes. We met near Baghdad before the war, when he was an ‘archaeologist’ at Carchemish.”

“You say ‘archaeologist’ as though it were some sort of joke.”