Lord Byron (seen above, in the white cloak) died on the 19th of April, 1824, exactly 197 years ago.
His death took place during the siege of Messolonghi, in Aetolia, by turkish forces, in the greek war of independence.
To his left, the two notable figures are (military clothes) Theodoros Kolokotronis and (civilian black suit) Alexandros Maurokordatos.
While the sentiment of unity is nice there, by 1824 the unity already was lacking, leading to a couple of greek civil wars while the war of independence was still being fought. Maurokordatos also didn't have good relations with most of the military leaders, including Kolokotronis (who is, by all accounts, the most important one in this war).
Btw, that was a time when such a thing as "german philhellenes" existed. Maurokordatos was head of half the army at the 1822 battle of Peta (in the same theatre of operations; Aetolia), where a regiment of foreigners also fought, under the command of Karl von Normann-Ehrenfels
It is said that Ehrenfels referred to Maurokordatos as "prince". Greek military leaders usually reserved less flattering names for him, including "errand-boy of (turkish controlled) Constantinople".