I'm new here and have been reading through the posts. What you're referring to is the Roman triumph. Wikipedia has an article about it:
https://en.wikipedia.org/wiki/Roman_triumph. Unfortunately for the conquered people of Roman military campaigns, their leader would be executed after this event on most occasions. Where the enslaved ended up depended on what skills they brought with them. Highly educated slaves and skilled artisans would lead much better lives than most people who were enslaved, who often ended up in work gangs on farms and in Roman mines where they probably wouldn't live very long lives.
