We adults stood close by, wrapped up in cloaks against the breeze and ready to dive in if little Julia and Favonia accidentally plunged overboard. To add to our anxiety, we could see all the crew making urgent attempts to work out where we were as we approached the long, low, famously featureless coastline of Egypt, with its numerous shoals, currents, rocky outcrops, suddenly shifting winds and difficult lack of landmarks. We were passengers on a large cargo boat that was making its first lumbering trip south this season; indications were that over the winter everyone had forgotten how to do this journey. The dour captain was frantically taking soundings and looking for silt in seawater samples to tell him he was near the Nile. Since the Nile delta was absolutely enormous, I hoped he was not such a poor navigator he had missed it. Our sailing from Rhodes had not filled me with faith. I thought I could hear that salty old sea god Poseidon laughing.

Some Greek geographer’s turgid memoirs had supplied oodles of misinformation to Helena Justina. My sceptical wife and tour-planner reckoned that even from this far out you could not only see the Lighthouse, shining like a big confusing star, but also smell the city wafting across the water. She swore she could. True or not, we two romantics convinced ourselves that exotic scents of lotus oil, rose petals, nard, Arabian balsam, bdellium and frankincense were greeting us over the warm ocean - along with the other memorable odours of Alexandria, sweaty robes and overflowing sewage. Not to mention the occasional dead cow floating down the Nile.

As a Roman, my handsome nose detected this perfume’s darkest under-notes. I knew my heritage. I came fully equipped with the old prejudice that anything to do with Egypt involved corruption and deceit.