In the past, as in the present, people had a tendency to think that their culture/people were superior to other peoples. Here are some examples.
In the Book Black Spark, White Fire, writer Edgar Poe describes how 1st century Roman author Vitruvius Pollio explained the alleged differences between the supposedly stupid blue-eyed, straight-haired European tribes of the north, and the dark-skinned, curly-headed Ethiopians of the south, both of which had military conflicts with the Romans:
Now while the southern peoples are of acute intelligence and infinite resource, they give way when courage is demanded because their strength is drained away by the sun; but those who are born in colder regions by their fearless courage are better equipped for the clash of arms, yet by their slowness of mind they rush on without reflection, and through lack of tactics are balked of their purpose... (from On Architecture)
In his view, Italians were in between North and South, between black and white, and were superior to both because they have the best of both worlds.
Italy presents good qualities which are tempered by admixture from either side both north and south, and are consequently unsurpassed. And so, by its policy, it curbs the courage of the northern barbarians, by its strength, the imaginative south. Thus the divine mind was allotted to the Roman state an excellent and temperate region in order to rule the world.
A 10th century Muslim Ibn al-Faqih al-Hamadani wrote:
The people of Iraq have...a pale brown color, which is the most apt and proper color... they do not come out with something between blonde,blanched and leprous coloring, such as the infants dropped from the wombs of the women of the Slavs and others of similar light complexion; nor are they overdone in the womb until they are burned, so that the child comes out something between black, murky, malodorous, stinking, and crinkly-haired, with uneven limbs, deficient minds, and depraved passions, such as the Zanj, the Somali, and other blacks who resemble them. The Iraqis are neither half-baked dough nor burned crust but between the two.
Like the Romans, the Chinese also thought themselves the center of the world. The modern name of China is "Middle Nation". An archaic name is "Central Plains". Chinese saw their civilization as a gift to the 'barbarians' on their borders. Lipman writes in "Familiar Strangers":
According to an ideological tenet held by many Chinese in premodern times, non-Chinese must either remain in... barbarism or they must... be transformed by the civilizing power of Chinese culture.