The Biblioteca Pública de Évora preserves two copies of Abraham Zacuto’s Almanach Perpetuum, a rare incunable connected to Jewish scientific knowledge, early printing in Portugal, and the technical culture of Iberian navigation.

Abraham Zacuto and the Almanach Perpetuum

Abraham Zacuto was a Jewish astronomer, astrologer, mathematician and physician, probably born in Salamanca around 1452. After the expulsion of the Jews from Castile in 1492, he came to Portugal, where he was connected to the court of King João II.

The Almanach Perpetuum was printed in Leiria on 25 February 1496, in the workshop of Abraão d’Ortas. It was based on Zacuto’s astronomical tables, calculated from the radix year 1473, and included solar and lunar tables used for astronomical calculation.

Translation and Portuguese navigation

The tables were translated from Hebrew into Latin by Mestre José Vizinho, Zacuto’s disciple and a physician connected to King João II. The work became part of the scientific instruments associated with Portuguese oceanic navigation at the end of the fifteenth century.

The Biblioteca Pública de Évora records that its two copies are kept in the Casa-forte of the library. In 2026, the institution marked the 530th anniversary of Abraham Zacuto’s Almanach Perpetuum with a conference by Professor Henrique Leitão, during which the two copies were exhibited.