In 2025, the Czech Republic marks 900 years since the passing of Cosmas (†1125) — the first chronicler of the Czech lands and author of the Chronica Boemorum (Chronicle of the Czechs). The National Library of the Czech Republic is honoring this anniversary with Kosmas 900, a year-long project exploring not only the chronicler and his work, but also the broader beginnings of Czech historiography.

Who was Cosmas? Dean of the Prague Chapter in his later years, he was the first — alongside the earliest hagiographers — to attempt a written history of the Czech lands. His Chronicle of the Czechs offers a vivid account of the nation’s earliest past, beginning with mythic origins and the arrival of the Czechs in their new homeland, and continuing up to his own lifetime. Drawing on Biblical stories, ancient Greek heroes, and above all oral traditions, Cosmas wove a narrative that emphasised the ruling dynasty, the spread of Christianity, and the Church as a positive driving force in history. In doing so, he helped shape not only how the past was remembered, but also the Czech lands’ place in Christian Europe, embedding them firmly within Latin (Western) culture.

The program opened with a panel exhibition in the cloisters of the historic Clementinum complex in Prague. Using Cosmas’s chronicle as its central thread, the exhibition shows how the recording and interpretation of historical events have evolved over the centuries. Special educational programs for schools accompany the display, reflecting the fact that the Chronicle of the Czechs remains a key part of Czech history teaching. A dedicated training course and teaching materials for educators are also in preparation, aiming to make this cornerstone of national history accessible to younger pupils while incorporating modern research perspectives.

The season’s main exhibition will be held in two of the Clementinum’s most beautiful spaces: the Mirror Chapel and the Clementinum Gallery. The Mirror Chapel will be transformed into a symbolic treasury, bringing together almost all surviving medieval manuscripts of Cosmas’s chronicle — many of them loaned from prestigious institutions such as the Bavarian State Library and the Austrian National Library. A highlight will be the Leipzig Manuscript, containing the only known medieval depiction of Cosmas himself. The National Library will also display treasures from its own collections, giving visitors a once-in-a-lifetime chance to see these works side by side.

This main exhibition will open on 25 September 2025 in the Mirror Chapel and will run for just one month — a rare, time-limited opportunity to view these exceptional artefacts.

The Clementinum Gallery will then explore the chronicle’s long-lasting impact on Czech historiography and culture, tracing how its narratives continued to shape the nation’s understanding of its past for centuries.

The anniversary celebrations also include two major publications: a richly illustrated exhibition catalogue (in both Czech and English) and Living Stories of Dead Princes by Tomáš Klimek. The latter examines how Cosmas’s work interacted with oral tradition — showing how some of the stories he recorded lived on well into the Enlightenment, long after the rise of modern critical historiography.

Nine centuries after his death, Cosmas remains more than a medieval chronicler; he is a storyteller whose work continues to shape the Czech historical imagination.

Image: National Library of Czech Republic