One of the great poets of the Greek Diaspora was Constantine Cavafy (1860-1933). He was born in Alexandria, Egypt, educated in England, lived in Constantinople and France. His sense of history, commitment to Hellenism, and frugal use of words make him one of my favorite poets.
"The Poseidonians forgot the Greek language
after so many centuries of mingling
with Tyrrhenians, Latins, and other foreigners.
The only thing surviving from their ancestors
was a Greek festival, with beautiful rites,
with lyres and flutes, contests and wreaths.
And it was their habit toward the festival's end
to tell each other about their ancient customs
and once again to speak Greek names
that only few of them still recognized.
And so their festival always had a melancholy ending
because they remembered that they too were Greeks,
they too once upon a time were citizens of Magna Graecia;
and how low they'd fallen now, what they'd become,
living and speaking like barbarians,
cut off so disastrously from the Greek way of life."
translated by E. Keeley and P. Sherrard
One dreary September day
Emperor Manuel Komninos
felt his death was near.
The court astrologers -bribed, of course- went on babbling
about how many years he still had to live.
But while they were having their say,
he remembered an old religious custom
and ordered ecclesiastical vestments
to be brought from a monastery,
and he put them on, glad to assume
the modest image of a priest or monk.
Happy all those who believe,
and like Emperor Manuel end their lives
dressed modestly in their faith.
C. Cavafy, 1915
Translation by E. Keeley and P. Sherrard
Additional poems in Greek as well as English can be found here.