Barbara ,
It has already been discussed here on Afrigeneas. around 1630 Cromwell sent 100,000 Irish to the New World English Colonies as SLAVES not oindentured servants, there is a site that explains it on the internet, i don't remember where I found the info. In St. Kitts and St. Nevins it is a big deal as about 30,000 went there.
There was a discussion on one of the boards about slave owners classifying Irish as mulattoes so that they could keep them enslaved.Southern slave states passed laws saying Irish could not be enslaved they had to be manumitted.