Gobineau's article attempting to rebut his critics in the Journal asiatique was not published, as the editors had to politely tell him his article was "unpublishable" as it was full of "absurd" claims and vitriolic abuse of his critics.[105] During his second time in Persia, Gobineau spent much time working as an amateur archeologist and gathering material for what was to become Traité des écritures cunéiformes, a book that Irwin called "a monument to learned madness".[105] Gobineau was always very proud of it, seeing the book as a magnum opus that rivaled the Essai.[105] Gobineau had often traveled from Tehran to the Ottoman Empire to visit the ruins of Dur-Sharrukin at Khorsabad, near Mosul in what is now northern Iraq.[105] The ruins of Khorsabad are Assyrian, built by King Sargon II in 717 BC, but Gobineau decided the ruins were actually Persian and built by Darius the Great some two hundred years later.[106]