On October 7, 1866, the Sultan Government delivered the final ultimatum to the Russian Envoy, demanding that the Russians hand over Constantinople within 48 hours or face war.
This declaration of war didn't even wait for the 48 hours to expire; upon receiving the ultimatum, the Russian Envoy replied directly, "Then let there be war!"
With the Ottoman Empire's large-scale war preparations, how could it be hidden from the Russians? As archenemies, the Tsarist Government had never relaxed its surveillance of the Ottoman Empire.
The Russian Ministry of Foreign Affairs also tried to woo the Ottomans, but they couldn't present any benefits, and the result was naturally fruitless.
Seeing the mobilization by the Sultan Government, Alexander II knew that war was inevitable.
One look at the map was all it took to confirm it. The Ottoman Empire didn't have many options, with a total of three neighbors around it.