The Decline of Classical Geography and the Rise of Symbolic Medieval Maps (c. 900 CE)

By 900 CE, the coordinate-based system of longitude and latitude—a hallmark of classical Greco-Roman cartography—disappears from Western European maps. This loss reflects the decline of classical geographical knowledge in the post-Carolingian period and marks a shift in the purpose and function of medieval maps.

Factors Contributing to the Loss of Longitude and Latitude

1. Decline of Classical Learning in the West

   • The breakdown of centralized Carolingian authority leads to a decline in scholarly institutions, particularly in the study of Greek and Roman scientific texts.
   • Knowledge of Ptolemaic cartography, which had been preserved in Late Antiquity, becomes increasingly inaccessible in Western Europe.

2. The Shift from Scientific to Religious and Political Cartography

   • Medieval maps become less concerned with precise geographic representation and instead emphasize religious, spiritual, and political themes.
   • The disappearance of latitude and longitude coincides with the rise of symbolic mapping traditions, such as:
     • T-O maps, which place Jerusalem at the center of the world and divide the continents into Asia, Europe, and Africa.
     • Mappa Mundi, which prioritize biblical history and sacred geography over empirical observation.

3. Lack of Standardized Measurements and Exploration

   • Unlike the Roman Empire, which had vast surveying and road-building infrastructure, medieval Europe lacks state-sponsored geographic research.
   • Navigation remains largely coastal, with limited need for coordinate-based mapping.

Consequences of the Shift in Cartography

• Maps become more schematic and symbolic, often used for theological instruction rather than practical navigation.
• Geographical distortions increase, as mapmakers rely on religious texts and travelers’ accounts rather than scientific calculations.
• Arab and Byzantine scholars preserve classical cartographic knowledge, ensuring that longitude and latitude will later be reintroduced to Europe through Islamic Spain and the Renaissance.

The Long-Term Impact

• The disappearance of coordinate-based mapping reflects the broader intellectual transformation of medieval Europe, where scientific knowledge is deprioritized in favor of theological worldviews.
• This loss is temporary; by the 12th and 13th centuries, renewed contact with Islamic and Byzantine scholarship will reintroduce classical geography to the Latin West, laying the groundwork for the Age of Exploration.

Thus, by 900 CE, medieval European maps cease to function as scientific tools and instead become expressions of Christian cosmology and political power, marking a significant departure from the geographic precision of the classical world.