A student at the Higher School of Commerce and a member of Epon, Theonas Mavromatidis lived in Athens. He was killed by German bullets on Omirou Street during the demonstration on July 22, 1943.
His grave was established by his father, Anthimos Mavromatidis, on August 16, 1946. It is situated near the grave of Kula Lili, a fellow student who was also murdered in the same demonstration. Both graves bear identical inscriptions dedicated to these young fighters of Epon.