The Litterae ignotae of Hildegard of Bingen

In the monastery of the Rupertsberg, near Bingen on the Rhine, a twelfth-century Benedictine abbess composed something no one before her had done in the West: a new alphabet, accompanied by a new language. The abbess was Hildegard of Bingen, born in 1098 and died in 1179, visionary, theologian, composer and author of treatises on natural science. Her Litterae ignotae, the unknown letters, are among the oldest invented scripts of the European Middle Ages whose author is known.

Twenty-three original signs

The Litterae ignotae are twenty-three letters, corresponding to those of the Latin alphabet used at the time. Their forms do not directly imitate any known script: they have stems, hooks and small oblique strokes that partly recall Gothic letters, but with a wholly personal design. Hildegard does not present them as a revelation from angels or ancient sages, but as part of her work, together with the Lingua ignota.

The letters are preserved in two main manuscripts. The most famous is the so-called Riesencodex, the giant codex, an enormous volume that gathers many of Hildegard's works and is kept in Wiesbaden. A second witness is in Berlin. In both the alphabet accompanies the glossary of the unknown language, and its copying shows the care with which the monastery handed down the abbess's work. The two copies are not entirely identical, and palaeographers have compared the forms of the letters in order to reconstruct the original model.

What they were for

Why Hildegard created this alphabet has been much debated. Some scholars think of a script reserved for the community of nuns, which strengthened the sense of belonging and unity of the monastery. Others see the letters as a mystical expression, an attempt to make visible a language purer than the common one. Hildegard herself left no detailed explanation, and every interpretation remains a hypothesis.

It is unlikely that the Litterae ignotae served to hide secrets in the modern sense of cryptography. They are not a cipher built on mathematical rules, and there is no evidence that they were used for confidential correspondence. They seem rather an object of devotion and ingenuity, born in a monastic setting where writing, music and prayer were closely intertwined. It is no coincidence that the letters appear in the manuscripts beside theological and musical works, and not among administrative documents or private letters.

The rediscovery

For centuries Hildegard's letters remained known to few specialists. Interest grew in the nineteenth and twentieth centuries, when the manuscripts were studied and published by German philologists, and even more in recent decades, with the success of the abbess's music and works. In 2012 Hildegard was proclaimed a saint for the whole Church and a Doctor of the Church, and her figure has enjoyed a new renown.

Today the Litterae ignotae are studied as an exemplary case of medieval creativity, far from the stereotypes of a static and closed age. In a small alphabet of twenty-three signs we see reflected the personality of a woman who, in a world dominated by men, managed to invent even a new way of writing. Whoever looks at them in reproductions of the Riesencodex can still sense the gesture of the pen that traced them, eight centuries ago, in a scriptorium overlooking the Rhine.