Awarded during his studies at the Athens School of Fine Arts (Ανωτάτη Σχολή Καλών Τεχνών) under professors Andreas V. Georgiadis and Yannis Kefallinos. This was the first of five academic distinctions recognizing his mastery of figure painting.

Recognition of his exceptional ability in outdoor painting — capturing light, atmosphere, and landscape directly from nature. Plein air painting would become the defining technique of his entire career, producing over 2,000 works across Greece, Spain, France, Italy, and the Netherlands.

Awarded for versatility across multiple media and artistic methods, demonstrating a rare command of both traditional and experimental approaches during his formative years at the Athens School of Fine Arts.

A fourth academic distinction, this time for drawing rather than painting — confirming Markellos’ complete mastery of the human form in both colour and line. The Athens School of Fine Arts recognized his technical precision and anatomical understanding.

A fifth academic distinction for nude painting, awarded in his final year of studies. This second consecutive recognition in nude studies confirmed his exceptional command of the human form and established his reputation before graduation.

The only distinction awarded in the diploma examinations of the 1953 graduating class at the Athens School of Fine Arts, for his work #5, “Female Nude.” This singular honour confirmed Markellos as the most outstanding graduate of his year.

During his studies at the Royal Academy of San Fernando in Madrid (1954–1957), Markellos received the rare honour of being granted official permission by the Museo del Prado to copy Francisco de Goya’s masterpiece “The Third of May 1808” (El Tres de Mayo de 1808). This privilege, reserved for artists of recognized skill, allowed him to study Goya’s technique at first hand — the dramatic use of light, the emotional intensity, and the monumental composition that would influence his own expressive approach to painting.

Markellos received an international distinction at the VI World Festival of Youth and Students in Moscow for his painting “Gypsy” (Τσιγγανα). The work represents the expressive realism characteristic of his early period, combining bold brushwork with emotional depth. This was among the first international recognitions of his talent beyond Greece and Spain.

In September 1963, Markellos was awarded the Targa Arte Fiorentina (Silver Medal) at the “Premio Mugello” — the 2nd National Competition Exhibition of Plein Air Painting, held in Scarperia, Tuscany. He participated as entry #89 among over 150 Italian and international painters. That same year, he held a highly acclaimed solo exhibition at Galleria Spinetti in Florence.

From 1948 to 1953, Markellos studied at the Athens School of Fine Arts (Ανωτάτη Σχολή Καλών Τεχνών), the most prestigious art institution in Greece. He trained under professors Andreas V. Georgiadis and Yannis Kefallinos, mastering figure painting, drawing, plein air techniques, and mixed media. He graduated in 1953 with the sole diploma distinction of his class.

In 1954, Markellos won a state scholarship from Spain, enabling him to enrol at the Royal Academy of Fine Arts of San Fernando (Real Academia de Bellas Artes de San Fernando) in Madrid. He studied there for three years, immersing himself in the great Spanish museums and the tradition of Velázquez, Goya, and El Greco. The Spanish period had a profound and lasting influence on his colour palette and approach to light.

In 1960, Markellos was awarded a university scholarship from the Athens School of Fine Arts and continued his artistic development at the École nationale supérieure des Beaux-Arts in Paris (1960–1962). During four formative years in the French capital, he absorbed the French artistic tradition and painted the city in all seasons and weather, producing his celebrated “Paris 1960–1962” series of nearly 100 works.

In 1997, Theodoros Markellos donated a significant collection of his paintings to the Municipality of Trikala, near the iconic Meteora. The gallery — Pinakothiki Theodorou Markellou — was officially opened on January 19, 1999. The collection comprises works personally chosen by the artist from his vast body of over 2,000 paintings.

Theodoros Markellos descends from the historically significant Markellos family, known since the Greek War of Independence in 1821. His great-grandfather, the revolutionary Spyridon Markellos, took part in the sieges of Corinth and Athens and served as representative of Aegina in the first national assemblies.

The Markellos Tower on the island of Aegina served as a revolutionary headquarters and administrative centre when Aegina was the temporary capital of Greece (1827–1829). Today it stands as a landmark of modern Greek history.