The traditional Chinese kingdoms operated under centuries of constraints on commerce. The building of walls on their borders had been a way of limiting such trade and literally keeping the wealth of the nation intact and inside the walls. For such administrators, giving up trade goods was the same as paying tribute to their neighbors, and they sought to avoid it as much as they could. The Mongols directly attacked the Chinese cultural prejudice that ranked merchants as merely a step above robbers by officially elevating their status ahead of all religions and professions, second only to government officials. In a further degradation of Confucian scholars, the Mongols reduced them from the highest level of traditional Chinese society to the ninth level, just below prostitutes but above beggars.