Regarding Amasya, Atatürk and the rise of the Turkish Republic:

On 30 April 1919, Mustafa Kemal Paşa (the future Atatürk), aged almost 38, general and Turkish hero of the First World War, was assigned as inspector of the Ninth Army Troops Inspectorate to reorganize what remained of the Ottoman military units and to improve internal security. This assignment occurred in Istanbul, which he soon after left by ship. On 19 May 1919, he reached Samsun. His first goal was the establishment of an organized national movement against the occupying allied forces. Mid June 1919, together with three of his earliest associates, he issued the Amasya Circular (letter), declaring the independence of the country was in danger. This first formal action would lead to the National Congresses of Erzurum (July/August 1919) and Sivas (September 1919), and ultimately to the establishment of the Turkish Republic.

The Atatürk Monument commemorates this ‘Amasya Circular’, in a somewhat allegoric form. So, half of the represented people were not really present at the actual event.
The sculpture group was made in 1981, designed by the Turkish sculptor Prof. Dr. Tankut Öktem (1940-2007).

Correspondent: J.M.Criel, Antwerpen.
Sources: Wikipedia & www.yesilirmakgazetesi.com