Gimpel Fils Gallery acquired a series of his paintings and exhibited them in New York.
Then he met the lithographer Michel Cassé, who became a very close friend. It is in his studio that Fassianos realized a large part of his engraving work. In 1971, he participated in the Venice Biennale.
Between 1972 and 1975 he exhibited at the Alexander Iolas Gallery in Paris, New York, Milan and Geneva. He also had a solo show in Athens at the Zoumboulakis Galleries, in collaboration with the Alexander Iolas Gallery. In 1972, he participated in the Sao Paolo Biennale while working with Elsa Ancia’s engraving workshop.