What do ancient slavery and American slavery have in common? Let's find out.

References:

Article 1, Section 9 (Importation Clause)

The Migration or Importation of such Persons as any of the States now existing shall think proper to admit, shall not be prohibited by the Congress prior to the Year one thousand eight hundred and eight, but a Tax or duty may be imposed on such Importation, not exceeding ten dollars for each Person.

Article 4, section 2 (Fugitive Slave Clause)

No Person held to Service or Labour in one State, under the Laws thereof, escaping into another, shall, in Consequence of any Law or Regulation therein, be discharged from such Service or Labour, but shall be delivered up on Claim of the Party to whom such Service or Labour may be due.

Preamble

We the People of the United States, in Order to form a more perfect Union, establish Justice, insure domestic Tranquility, provide for the common defence, promote the general Welfare, and secure the Blessings of Liberty to ourselves and our Posterity, do ordain and establish this Constitution for the United States of America.

ARTICLE I, SECTION 2, CLAUSE 3 (Three-fifths Clause)

Representatives and direct Taxes shall be apportioned among the several States which may be included within this Union, according to their respective Numbers, which shall be determined by adding to the whole Number of free Persons, including those bound to Service for a Term of Years, and excluding Indians not taxed, three fifths of all other Persons.

References for Ancient Slavery:

Thomas, Hugh. The Slave Trade: The Story of the Atlantic Slave Trade: 1440-1870 . Simon & Schuster. Kindle Edition. Loc 492, 253, 355, 430.

Davis, David Brion, The Problem of Slavery in Western Culture (New York: Cornell University Press). Page 47, 49, 56.