The medieval Serbian army was well known for its strength and was among the strongest on the Balkans before the Ottoman expansion. Prior to the 14th century the army consisted of Byzantine-style noble cavalry armed with bows and lances (replaced with crossbows in the 14th century) and infantry armed with spears, javelins and bows. With the economic growth from mining, mercenary knights from Western Europe were recruited to finalize and increase the effectiveness of the army, especially throughout 14th century.