Use this palaeographic utility to apply a stated dating, script, abbreviation, codicological, metrological, layout, or condition rule consistently while preparing manuscripts for scholarly review.

Reference

Reference day named in the date.

Count

Ante diem count (2 = pridie).

Named month

Month named in the date.

Leap year

True for a Julian leap year (February has 29 days).

Convert a Roman-style medieval date ('ante diem n kalends/nones/ides of month M') into a day of month by exact inclusive backward counting, with the Ides on the 15th of March/May/July/October and the Nones eight days earlier; leap-year Februaries use the 29-day mapping (medieval scribal practice around the bissextile varied). The tool evaluates the supplied inputs together and returns the named outputs below; it does not infer omitted operating conditions or change the units shown.^[1]

Day

Day of month the notation resolves to.

Resolved month

Calendar month containing the date.

Reference day

Day-of-month of the reference day itself (kalends 1, nones 5 or 7, ides 13 or 15).

Roman notation

Classical abbreviation of the input, e.g. 'a.d. iii kal. apr.'.

• Script and manuscript evidence varies by language, region, institution, period, scribe, material, restoration, and cataloguing convention. A heuristic flag or score is not an authoritative date, hand attribution, reading, provenance, or conservation diagnosis.
• Use finite inputs in the displayed units and preserve more precision than the final presentation requires. Independently verify safety-critical, financial, compliance, or production decisions.

Retain page images, scale, foliation, material, provenance, diplomatic transcription, uncertainty, and comparison exemplars; confirm conclusions with codicological context and specialist judgment.

• Byzantine Anno Mundi Converter

  Convert an AD year and month into the Byzantine Anno Mundi year that begins on 1 September (AM = AD + 5509 from September, else AD + 5508) with its 15-year indiction counted from the first indiction of AM 6821 (September 312).

• Regnal English Year Converter

  Convert an English regnal year into its exact calendar span by anniversary arithmetic from each monarch's documented accession or coronation date to death or deposition (Julian calendar, modern year numbering; Henry VI covers only his first reign).

• Ampersand Era Mapper

  Check whether an ampersand style fits a century against the stated band table (classical Et ligature 1st-4th c., Caroline rounded 8th-12th, Gothic compressed 13th-15th, humanist roman 15th-21st) and list all styles the century admits.