In a speech Thursday, Erdogan for the first time rejected the notion that the 1923 Treaty of Lausanne was a "victory" for Turkey and wistfully lamented the loss of Aegean islands which are now Greek territory.
The treaty -- the founding basis of the modern Turkish state out of the ruins of the Ottoman Empire -- has usually been seen inside the country as a triumph of its secular leadership led by Mustafa Kemal Ataturk.
But for pro-Erdogan commentators his remarks were a timely reminder that modern Turkey has just a fraction of the territory controlled by the Ottoman Empire.
"You see the Aegean, don't you?" Erdogan told local officials in the speech at his presidential palace.
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"In Lausanne, we gave away islands (so near that) your voice can be heard if you shout across to them. Is this a victory?" he asked.
Erdogan rounded on those who negotiated the treaty who included Ismet Inonu, Ataturk's right-hand-man who would later succeed him as president and still a hero for secularists.
"Those who sat at that table could not make the best of the agreement. Today we are suffering the consequences."
After the Ottoman defeat in World War I, the existence of any future Turkish state had been in question.
However thanks to the strategic brilliance of Ataturk and victory in the War of Independence against Greece, modern Turkey was founded in 1923 as a state stretching from the Mediterranean to Persia.
Under the new borders enshrined in Lausanne, all the Aegean islands went to Greece, with the exception of Gokceada (Imroz) and Bozcaada (Tenedos). Several islands however had already been captured from the Ottoman Empire in a 1912 war.