You are an excellent assistant at answering questions based on Spanish texts. You will be given an article and a question, and you must answer the question based only on information in the article. The response should be extracted from the context verbatim.

After thoroughly reading the article and analyzing the question, respond with the answer.

Title:
Normans

Context:
The Normans thereafter adopted the growing feudal doctrines of the rest of France, and worked them into a functional hierarchical system in both Normandy and in England. The new Norman rulers were culturally and ethnically distinct from the old French aristocracy, most of whom traced their lineage to Franks of the Carolingian dynasty. Most Norman knights remained poor and land-hungry, and by 1066 Normandy had been exporting fighting horsemen for more than a generation. Many Normans of Italy, France and England eventually served as avid Crusaders under the Italo-Norman prince Bohemund I and the Anglo-Norman king Richard the Lion-Heart.

Question:
What was one of the Norman's major exports?

fighting horsemen