Thank you for your message,
The dates you mention are very early and unfortunately, the reality of finding documentation pertaining to births/baptisms/marriages/deaths in Ireland prior to 1800 ? particularly in rural areas ? is that they simply may not exist.
Do you have any other information that you can share? Do you know when they emigrated? Were they married? dii they have children before they left etc.?
Remember to post as much information as you can with regard to the people you are researching. The more information you post, the more likely it is that one of our volunteers will be able to advise or assist you. Also include information concerning which sources you may have already used so others may further your search.