Dual-Era Reckoning

Aethermourne keeps time the way it keeps cargo: in duplicate, with ledgers that must agree before anyone pretends the day is innocent.

Ember Age index (AE)

Coastal city-states and harbor tiers record civil years as AE, Aethermourne Ember, counted from the settlement charter that followed the First Ley Surge. An AE year is solar enough for markets and mourning; the decimal suffix is not a month but a tide fraction—how far the city's ley harmonics have advanced through the annual breathing cycle measured at Veilspire's crown orrery.

AE-414.6 therefore means: the four hundred fourteenth Ember year, six-tenths through the crowned tide count. Guild chutes, flight cradles, and Syndicate depositions cite AE fractions because harbor machinery was built to click with those harmonics, not with abstract months.

Mirror Spring index (MS)

Sealed laboratories, salt-flat expeditions, and symposium charters use MS, Mirror Spring, a parallel index ratified at the Glass Consensus Symposium. MS years do not convert cleanly to AE years. They track revision cycles of instruments—storm glass batches, triad seals, cartographic filings—rather than the sun over the harbor.

MS-11.6 means: the eleventh Mirror Spring revision cycle, six-tenths through the consensus triad's agreed measurement window. When a door beneath the flats bears REV B, it is MS grammar: the index admitted a correction after the first survey was already law.

Institutions that must speak to both worlds—harbor lockstep reviews, cross-era testimony—carry dual stamps. Disagreement between AE and MS on the same event is not heresy; it is data, filed until an orrery or storm glass forces reconciliation.

Operational units

Clocks exist. Auditors distrust them.

Breath — The interval a sealed room or chute counts between permitted actions. "Breath due" is not metaphor on the Ash Stair; counterweights and neutral ink bill by lung-count when sigil-stability fields thin the air.

Gap — A spent breath left empty. Two gaps on a plaque means two chances to arrive before arithmetic closes the line.

Dawn — In Veilspire, the hour when night stops pretending ledgers sleep and flight cradles learn their load. On the salt flats, dawn margin is the symposium hour when indices above pretend to rest while bearing pools still debit footsteps.

Margin — Cartographic offset between a published line and a walked line. Margin can be spent, stolen, returned, and witnessed the way coin is—especially where unlicensed filament insists on law.

Who keeps which book

The Iron Syndicate prefers AE fractions on manufactories and deposition cylinders; torque receipts click to harbor tide. Mirror schools and expedition charters file MS revisions first and negotiate AE stamps second. Neutral ink—where it appears—writes in whichever index the wall was calibrated to hear.

Travelers learn quickly: ask not only what year but which index, and whether the day expects breath, tide, or revision.