Why did Napoleon dismiss Arthur Wellesley as a “Sepoy general”?

Napoleon dismissed Arthur Wellesley, the 1st Duke of Wellington, as a "Sepoy general" to diminish his military reputation by associating him solely with his earlier service in India.1

The term "Sepoy" referred to the native Indian soldiers who served in the East India Company army. By using this label, Napoleon intended to imply that Wellesley’s experience was limited to colonial warfare against non-European forces, rather than the high-level strategic combat required to face the French military in Europe.1

This characterization was ultimately unwise, as Wellesley had developed the very qualities that would later lead to his success on European battlefields—such as meticulous attention to detail, effective supply management, and strong leadership—during his time in India.1