Where did most of the slaves come from in rome?

People became slaves among the Romans by the following ways:

By being taken in war 

By way of punishment 

They were born in a state of servitude.

the roman army grew in size and became dominant in the mediterranean region.

united states reinforcements contributed greatly to three allied victories in france at: cantigny (first major american battle), argonne (the largest in the united states military history, involving 1.2 million american soldiers), and château-thierry (one of the first actions under general pershing).