Many thanks Luis for this very nice registered cover, sent on Oct 1st, from Lisbon where the Portugal 2010 World Philatelic Exhibition was held ;-))) The stamp issue of Ceres - 100 Years of the Republic of Portugal was issued in conjuction with Portugal 2010 World Philatelic Exhibition.
This stamp issue revived the Ceres definitive stamp series depicting the Roman goddess Ceres that was issued between 1912 and 1945 in Portugal and its colonies.
Also, this year marks the centenary of the proclaimation of the Portuguese Republic. The Portuguese First Republic was established on Oct 5, 1910 following the revolution of 1910 which deposed King Manuel II.
This new Ceres stamp reinterprets Constatino Fernandes' original design from 1911 by means of a technique that combines intaglio and offset.