Roman Numerals During the Middle Ages

At the same time, the figures now called Hindu–Arabic numerals gradually entered western Europe. The change was not immediate. For centuries, Roman numerals, Hindu–Arabic figures, written number words and physical counting methods existed side by side.

A medieval book could therefore contain Roman chapter numbers, Roman folio numbers, letters and numerals marking its folded sheets, and Arabic figures added by a later reader. Each system was being used for a particular job.

Key takeaways

• Roman numerals remained useful throughout the Middle Ages.
• Medieval scribes used them for chapters, psalms, folios, quires, dates and quantities.
• Foliation numbers leaves; pagination numbers individual page sides.
• Quire signatures helped book makers assemble folded sheets in the correct order.
• Roman numerals often recorded values while calculation took place separately.
• Hindu–Arabic numerals spread gradually rather than replacing Roman numerals at one moment.
• Numbering visible in a manuscript today may have been added centuries after the book was made.

Medieval practice was not completely uniform

The Middle Ages covered many centuries and highly varied communities. A monastic manuscript, a merchant’s account and a fifteenth-century printed book were produced for different readers and purposes.

Numeral practice therefore varied across regions, periods and types of document. The most useful question is not, “How did medieval people always write this number?” It is:

What was this number doing in this particular document?

How Roman numerals organised medieval books

A medieval manuscript was usually made from sheets folded into groups called quires or gatherings. Before the book was bound, its sections and leaves had to be kept in the correct order.

Roman numerals could help organise several parts of the book:

These systems served different purposes. A chapter number organised the subject matter, while a quire signature helped control the physical construction of the book.

Foliation, recto and verso

Modern books usually number pages. Manuscript catalogues often describe folios, meaning leaves.

Each leaf has two sides:

12r = the front, or recto, of leaf 12
12v = the back, or verso, of leaf 12

Foliation gives one number to the whole leaf. Pagination gives a separate number to each side. A manuscript with 100 folios may therefore have about 200 usable page surfaces.

The visible folio numbers are not always medieval. Some were added by later owners, librarians or cataloguers. One Bodleian catalogue, for example, identifies Roman-numeral foliation added in the sixteenth century rather than by the manuscript’s original makers.

A Roman numeral written on old parchment must therefore be dated before it can be treated as evidence of original medieval practice.

One manuscript, several numbering systems

St John’s College MS 64, copied in 1414, provides a useful example. Its catalogue records original Roman-numeral foliation at the top of the leaves. Letters combined with Roman numerals mark leaves within the quires, and Roman numerals in the running titles identify the psalms.

In the sixteenth century, Arabic numbers were added on the facing sides of the leaves.

The manuscript does not show one system instantly replacing another. It preserves several layers of use:

• Roman numerals for the original foliation;
• letters and numerals for the book’s physical organisation;
• Roman psalm numbers in the running titles;
• later Arabic figures added by another reader.

Other manuscripts use different combinations. One fifteenth-century Gospel book uses Roman numerals for many chapter numbers but letters for its quire signatures. British Library catalogues also record gatherings marked with Roman numerals.

Records, dates and accounts

Roman numerals were not confined to books. Churches, monasteries, courts, towns and royal administrations all produced records requiring dates, quantities and ordered references.

Numerals could identify:

• a ruler’s regnal year;
• a date or feast-day calculation;
• land, goods or money in an inventory;
• numbered clauses or entries;
• quantities in an account;
• a document’s position within a series.

Their meaning depended on the words and units around them. A written xii might refer to coins, measures, years, people or items in a list.

The surviving evidence is weighted towards institutions that preserved documents. It shows how numerals were used in those settings, but it cannot represent every household or occupation in medieval Europe.

Recording a number was not always the same as calculating it

Roman numerals could record a quantity without being the main tool used to calculate it.

Counting boards allowed users to arrange movable counters in positions for units, tens, hundreds and larger values. The completed result could then be written in Roman numerals, number words or another notation.

Hindu–Arabic numerals later made written calculation much easier, but that advantage did not cause every established recording practice to disappear immediately.

The gradual arrival of Hindu–Arabic numerals

The decimal figures used today developed from Indian numeral traditions and reached western Europe through Arabic-language mathematics and other routes of transmission.

They were known in parts of Europe before Fibonacci. His Liber abaci, written in 1202 and revised in 1228, became an influential explanation of calculation with the nine figures and zero. It applied the system to practical problems involving prices, profit and currency conversion.

Fibonacci did not single-handedly introduce these numerals to Europe, and his readers did not abandon Roman numerals at once. His work circulated in handwritten copies before printing, and the newer methods required training and familiarity.

Roman numerals still suited many established tasks:

• numbering a chapter;
• labelling a list;
• recording a total;
• following a church, legal or administrative convention.

Hindu–Arabic figures were increasingly useful for written arithmetic. The two systems could therefore be used for different purposes within the same community.

Early printing continued older habits

Movable-type printing developed in Europe during the fifteenth century, but early printed books often resembled the manuscripts familiar to their readers.

Printers retained features such as abbreviations, decorative initials, quire signatures and Roman numbering. The 1475 Rudimentum novitiorum, for example, contains Roman-numeral foliation within sections of the work.

Printing could preserve established Roman-numeral roles even while helping mathematical texts and Hindu–Arabic figures reach larger audiences.

The detailed explanation of why Hindu–Arabic numerals eventually became dominant belongs to Roman Numerals vs Hindu–Arabic Numerals: Why the Modern System Replaced Them. Medieval evidence shows the transition taking place, not its final outcome.

Why medieval Roman numerals may look unfamiliar

A medieval numeral may differ from the standard modern form because:

• it is written in lowercase;
• the scribe used an additive form;
• the final character has a j-like shape;
• letters are joined or abbreviated;
• the numeral belongs to a money or measurement system;
• part of the text has been damaged or trimmed;
• later numbering has been written beside the original.

Historical records can therefore show forms such as iij for 3 and iiij for 4.

A modern catalogue may also convert Roman foliation into Arabic figures for the reader’s convenience.

None of this means that every arrangement was acceptable. It means that the numeral must be read with its handwriting, date, unit and purpose in mind.

How to approach a medieval numeral

When a numeral appears in a manuscript or historical record, ask three questions:

1. What is it numbering?

A leaf, chapter, gathering, year, quantity or amount of money?

2. When was it added?

Is it contemporary with the manuscript, written by a later owner or supplied by a modern library?

3. What surrounds it?

Words, abbreviations and units often explain the value more clearly than the numeral alone.

This prevents a later folio number from being mistaken for original medieval evidence and stops a production mark from being read as part of the main text.

A gradual transition

Roman numerals survived because they continued to do useful work. They organised manuscripts, labelled sections, recorded dates and quantities and fitted long-established institutional practices.

Hindu–Arabic numerals offered a stronger system for written calculation, but their spread depended on education, copying, commerce and access to texts. Medieval books preserve the overlap: Roman numerals, Arabic figures, number words and physical counting methods could all belong to the same numerical culture.

One notation did not simply vanish on the day another arrived.

Continue exploring

• The History of Roman Numerals
• Why Some Roman Numerals Look Different: Historical and Non-Standard Forms
• How Romans Calculated: The Abacus and Counting Boards
• How Ancient Romans Used Roman Numerals
• Roman Numerals in Books, Page Numbers and Outlines
• Roman Numerals vs Hindu–Arabic Numerals: Why the Modern System Replaced Them
• Where Did Roman Numeral Symbols Come From?