An empire made from a tribe. Just like it says. The Mexica (Aztecs) were one.
Another great example is Qing China.
The Ohio River is a tributary of the Mississippi River. In the ancient world, Egypt became a tributary of the Roman Empire.
http://www.historyforgrownups.com/graphics/guptaempiremap.gif
Because a tributary flows into a river. If a tributary flowed directly into the sea - it would be a river - not a tributary !
a tributary is a stream
It is called a tributary
A tributary.
A Tributary
Certificate of Tributary Information
A tributary is water.
neasho tributary
Cyrus the Great expanded Persia from a tributary state of the Medes into an empire covering the Middle East and Central Asia.
The Tang Empire required that any country that wanted to do trade with and keep peace with them had to pay a tribute. Countries that participated included Korea, Vietnam, Japan, and more.