Cataloguing Eras

The Cataloguing Eras are the primary divisions of the Tower's administrative and philosophical history, designated not by strict sequence of years but by prevailing doctrines of how things ought to be recorded. An Era is not a span but a disposition: it names the manner in which the Tower catalogued during a period, and only secondarily the period itself. The current disposition is designated Present Era, a title retained despite three separate motions to rename it, each of which foundered on the question of what would succeed it.

Era designations are formally ratified under the Manual of Temporal Cartography, which distinguishes Eras from States, Apertures, Spirals, and Interregnums and enumerates the conditions under which one may lapse into another. The Spiral Calendar supplies the metachronological framework in which those transitions are contextualised, and is not, as is frequently supposed in the upper reading rooms, a means of dating anything.

Enumeration

The First Cataloguing Era is held to have begun with the laying of the first catalogue shelf, though no shelf has been produced to substantiate this and the claim rests on a marginal gloss in a copy of the Concordance of Shelving of uncertain recension. The First Era is generally characterised by descriptive accumulation: things were entered, and entered again, and the entering was considered the work.

The Second Cataloguing Era opened with the promulgation of the Cataloguing Protocol and its insistence that an entry conform to a recognised class. Its partisans describe it as a correction; its detractors, including most of the Sub-basement Cataloguing Corps, describe it as a loss. The Third Cataloguing Era is conventionally dated to the winter following the Re-cataloguing Authority (RCA)'s assumption of audit functions on Floor 8,114, though the RCA itself records the date a year earlier and declines to reconcile the two accounts.

Verification and Closure

No Era is understood to have ended merely because its successor has begun. The Kairologos performs the Verification of Closure for Eras, a procedure by which the Office of Verification adjudicates whether a terminated catalogue, operation, or Era may be considered administratively final. Closure is not automatic and is rarely prompt. The Second Era was verified closed in C.E. 3,102, more than two centuries after its last entries were made, and the verification was contested the following year on the ground that certain of its practices had continued in the Department of Ephemeral Cataloguing under other names.

"An Era is not concluded when it ceases to be practised. It is concluded when it ceases to be cited."

— Office of Verification, Ruling 41 (on the Second Era), Annex 2

The distinction matters practically. Eras that have not received Closure remain cited in dispute proceedings under Cataloguing Dispute Resolution, which means an unresolved Era can be pleaded indefinitely. The First Era has never been closed, and a school of cataloguers on Floor 292 has built a considerable body of argument upon the fact.

The problem of retroactive entry

Entries made in one Era but filed in another must be converted before they can be cited, a procedure governed by the Elaran Protocol, which controls the retroactive conversion of events from the First and Second Eras into C.E. dates. The Protocol has been amended eleven times, most recently to accommodate the discovery that a quantity of First Era material had been filed throughout under Third Era conventions by a clerk who did not wish to open a second ledger.

The Edict of Temporal Conflation was ratified under Series Ω in an attempt to standardise the reconciliation of such contradictions, and was itself superseded by a measure that repealed the Conflation while preserving its annexes. The annexes remain in force. The Department of Cataloguing Consistency has ruled that this arrangement, while irregular, is not contradictory, and has declined to elaborate.

Scholarly disagreement

The central dispute of Era studies concerns whether the Eras succeed one another or overlap. The successionist position, maintained by the Department of Substantive Cataloguing and consistent with its accreditation of the Realist School, holds that an Era properly begins when its predecessor's Closure is verified, and that the apparent overlaps are artefacts of slow filing. The overlap position is advanced most forcefully in the Office of Atmospheric Cataloguing, whose Ambient Cataloguing Haze Theory permits an Era to persist in attenuated form wherever its habits remain in use, irrespective of any formal termination.

The overlap position has the practical advantage of explaining the Cataloguing of Ephemera, during which Comparative Distal Cataloguing is most frequently invoked precisely because material from several Eras is being handled at once. It has the doctrinal disadvantage of rendering Closure advisory, a conclusion the Office of Verification has never accepted and has twice publicly regretted not having foreseen.

Disputed Eras

Several proposed Eras have been advanced and not ratified, among them the so-called Interregnum Era of the long stair between Floors 5,000 and 5,040, proposed in C.E. 1,988 and rejected on the ground that a stairwell is not a doctrine. The Provisional Cataloguing of the Fourth Era, begun in C.E. 3,401 by the Re-cataloguing Authority (RCA) under the authority of the Great Re-cataloguing, remains incomplete and is filed, for the present, under the Present Era as a subheading.

The Later Cataloguing Era, proposed by a single clerk of the Sub-basement Cataloguing Corps in a memorandum of C.E. 3,395, has never been formally rejected. It has instead been referred to the Department of Cataloguing Consistency for an opinion on its relation to the Present Era, and the Department has held the referral for eleven years. The clerk's name is recorded in the referral slip; the memorandum itself is lost. No further action is expected.