Final answer:
The estimated distance from the city of Tours to the Spanish March, specifically Barcelona, is around 500 miles. This distance reflects modern-day road measurements and not precise medieval travel routes.
Step-by-step explanation:
The distance from the city of Tours, located in France, to the Spanish March, a buffer zone created by Charlemagne during the 8th century along the Spanish border, is historically significant but not a fixed numerical value due to the varying interpretations of the geographical extents of the March at different times. However, if we consider the distance from Tours to the city of Barcelona, one of the central areas often considered to be within the Spanish March, we can estimate this historical route.
During the medieval period, routes and distances were not measured with the precision we have today, but we can estimate that the distance from Tours to Barcelona is roughly 500 miles (800 kilometers). This estimation is based on modern-day road distances, which might not directly correlate to medieval travel routes.
Tours in northern-central France and the Spanish March in the northeast of modern-day Spain were crucial points in the medieval Frankish kingdoms, illustrating the significance of their territorial reach and defense strategies against Islamic invasions from Al-Andalus.