linealأمة

A conquered people is marginalized. As it blends with the conquerors, peoples from further away see the ruling people and subjected people as one. The subsumed and dwindling subjugated become a quirk -a subculture- within the wider victorious culture. There's habit-drift: defining traits of the subjects join the practices of the masters and vice versa. Traditions are shared and connect people in an amalgam culture.
Take the name of any nation. Where did its' people come from? One assemblage of tribes conquered others. Both blend together until they forget the names of their clans. Borders are islands where enemy garrisons sit across from one another in an ocean of peoples.
Sometimes the newborn culture takes after its' father, the conqueror, and bears his name. Like Tsaritsyn became Stalingrad became Volgograd. Sometimes the amalgamation takes after its' mother, the subjected people/s, like England stayed English after the Norman Conquest.
A conquering people are carriers. They harbor fragments of other peoples' personalities in their psyche. Over time some fragments spread, transforming the host from the inside out. Like Romans became Greek then Christian.
People who know themselves to be a separate culture but don't know their ancestors ways have a tabula rasa to be iconates. Like America's freedmen buying clothes it'd take years to grow into.