By 1922, the Bank of Athens had branches throughout Greece, as well as in Limassol and Nicosia in Cyprus, Alexandria, Cairo, and Port Said in Egypt, Galata, Stamboul and Pera in Constantinople, Adrianopolis in "the former Turkey in Europe", and London and Manchester in England.
De Mango was among the artists who, at the initiative of Alexander Vallaury, a teacher in the architecture department of the School of Fine Arts, and Regis Delbeuf, manager of the Istanbul daily Le Stamboul, organized the first painting and sculpture exhibition at Beyoğlu in 1901, dubbed the ‘Pera Exhibitions in the Passage Oriental’, an arcade owned by the French merchant Bourdon.