Modern diplomacy makes extensive use of communications between diplomatic missions, institutions and different states. During the pre-modern times it was not a common practice that leaders exchanged letters when campaigning for warfare against each other. The Ottoman Sultan Selim I and Safawid Shah Ismail just did that. My paper analyzes contents of the letters as a war diplomacy exchanged between the two leaders before the war of Chaldiran in 1514. Based on the primary sources (mostly in manuscript and print form in Persian and Ottoman Turkish) my paper deals with a very interesting set of letters between Selim I and Shah Ismail during Selim's campaign against the Shah. Selim writes that he is in the lands of Shah seeking for him; but he is nowhere to be found. Selim says that he left some 40.000 of his troops on the way around Sivas that he is coming with fewer soldiers. “No need to be afraid; what else one could do for the enemy!” Shah replies that he was out for hunting; that these words were incomprehensible; perhaps must be penned by opium using scribes of Selim. Shah’s letter was accompanied with a stamped box–for the Selim’s scribes’ careful use to avoid overdose!” Letters and exchange of gifts humiliating nature continue until the two armies faced each other. Rich in content and creativity, these letters demonstrate a psychological warfare taking place also between the two leaders. Though there is no evidence in the records indicating that these letters were read out loud to the public aggressive language, humiliating choice of words and exchange of humiliating gifts were used as complementary to war diplomacy targeting the morale of the enemy. My article made extensive use of the following sources; including but not limited to: Feridun Bey’s Munshaat al-Salatin (especially the Persian sections), Mustafa Ali’s Kunh’ul Akhbar along with the poems written by Selim and Shah Ismail and several Selimnames (including the ones by Edai-yi Shirazi, Idris-i Bitlisi, Shukri-i Bitlisi, and Celalzâde Mustafa.)