Twice on [his] antiquarian tour [of Italy and Greece in 1911-12], the Oxford don-elect was arrested as a Turkish spy, first on the evening of the 16th November, 1911 on the last lap of a day’s march from Terracina to Formia, by an Italian carabiniere [Footnote: On this occasion, the suspect was able to clear himself by showing a card with “Balliol College, Oxford” engraved on it. “Ah! Collegio! Dunque non siete Turco”, reasoned the intelligent Italian security officer, and straightway left the left the suspicious-looking traveller in peace. Forty years later, in A.D. 1952, the carabiniere would, of course, no longer have been justified in acting on an a priori assumption that “Turk” and “college” were incompatible ideas.]
The Italians had every reason to be spy-conscious: their war with the Ottoman Empire, which gave them Libya and the Dodecanese (Rhodes), had begun at almost the exact moment Toynbee arrived in Italy. It ended soon after his return from Greece. (They held both colonies until the Second World War. The Dodecanese were returned not to Turkey but to Greece.)
and then again, on the 21st July, 1912, by a Greek military patrol. [Footnote: On this second occasion, he was arrested on the reasonable charge that he had walked across the perilously vulnerable railway viaduct over the gorge of the River Asopus at Elefterokhóri, where the sole railway running from Athens to the Graeco-Turkish frontier leaped across a chasm to come to earth again along the eastern flank of the citadel of Trachis. This charge was supported by the less convincing argument that the trespasser must be a foreign military spy because he was wearing insignia in the shape of a military water-bottle that was not of the pattern affected by the Greek Army.]
The Balkan Wars began a few weeks after his return to England.
A Study of History, Vol X, OUP, 1954