دانلود کتاب Late Antique Calendrical Thought and its Reception in the Early Middle Ages

The essays in this volume emerged from papers presented at the 3rd International
Conference on the Science of Computus in Galway in July 2010.
The conference was established in 2006 and has since been held biannually.
It may be fair to say that before this date, the late antique and medieval
science of computus was safely in the hands of only a few specialists.1
Computus is a decidedly Christian science of calendrical calculations,
which evolved around the need to establish the date of Easter.
Since the third century, Easter was supposed to fall on the first Sunday
after the first full moon after the spring equinox, as is still the custom
today. Therefore, its calculation depended, from a late antique and medieval
perspective, on the mathematical modeling of the tropical year (the
Julian calendar) and of the lunar phases—the synodic lunar months, i.e.
the periods from one new moon to the next (84-year or 19-year lunar
cycle). From the seventh century onwards, computus evolved from its
core purpose of calculating Easter to become a more wide-ranging subject
explaining the natural world as part of the quest of understanding
God’s creation.