Theodore John (Iannis) Coronio (Koronios) was a merchant and collector. He was a British subject but was born in Syra. He was the son of Zannis (or Iannis, ie. John) Coronio (Koronios), who was born in Chio in 1794 and died in Syra in 1886. He had a brother Georges Coronio who was a broker, banker and collector. He was married to Aglaia Coronio, née Ionides.
Theodore Coronio lived at 1A Holland Park, next to Alexander Ionides, from 1869. Through Ionides, JW made friendships with the Greek community in London, including with the Coronios. Theodore Coronio bought a number of JW's works and through JW also became a patron of Henri Fantin-Latour. JW acted as go between, sending Fantin's pictures to Coronio and collecting the payment. JW advised Fantin to charge Coronio and Ionides 100 francs for a small picture and 300-350 francs for a large one as his works became more fashionable. Coronio also recommended his work to Michael Spartali.
1901 census; Ionides, Luke, Memories, Paris, 1925; Maurier, Daphne du, The Young George Du Maurier, London, 1951; Argenti, Philip, Libro d'oro de la noblesse de Chio, Oxford, 1955; Druick, Douglas and Michael Hoog, Fantin-Latour, Ottawa, 1983; Dakers, Caroline, The Holland Park Circle: Artists and Victorian Society, New Haven and London, 1999.