04 — The Julian Calendar

What the Julian calendar is, where it came from, why the Church inherited rather than legislated it, what Gregory XIII changed in 1582 and how the East answered — and then the technically decisive point of the whole collection: the drift affects the fixed calendar, while the received Paschalion is a separate reckoning that comes apart from it.

Tradition: Pan-Orthodox

Contents

File Description
what-the-julian-calendar-is.md Caesar’s reform, decreed 46 BC and effective 45 BC; the bissextile day and the Augustan correction; the Indiction and the Byzantine era; Inter gravissimas and the ten deleted days of October 1582; the synods of 1583, 1587, and 1593 under Jeremias II — and a structured disposition on the “Sigillion of 1583,” which this library does not rely on
the-drift-and-what-it-does-and-does-not-affect.md Eleven minutes a year, one day in 128 years, thirteen days now and fourteen from 2100; what the drift moves and what it cannot touch; why the Paschalion is a separate computation whose Julian output is merely expressed on a civil grid; the two errors by which the drift reaches Pascha after all; and the seam at which the Apostles’ Fast sits

The Mechanism, in One Paragraph

The Paschalion consumes a golden number and an ecclesiastical equinox defined as 21 March Julian, and returns a Julian date between 22 March and 25 April. That date is then translated into whatever civil calendar the local church uses. Because the last step is only a translation, a church can change the calendar on which it keeps its fixed feasts without touching the Paschalion at all — which is exactly what the Revised Julian churches did, and why every Orthodox Church save Finland still keeps Pascha on the same day.

The corollary a reader should carry away: “thirteen days behind” is true of the fixed calendar and false of Pascha. Orthodox Pascha is later than Western Easter by nothing, seven, twenty-eight, or thirty-five days — never thirteen.

Reading Order

what-the-julian-calendar-is.md, then the-drift-and-what-it-does-and-does-not-affect.md, which is the file section 05 and section 06 both depend on.

See Also