Pender/ and Pepper

I am trying to locate information regarding William Pender. He was born in 1781. Any information regarding his parents or other ancestors would be greatly appreciated. The following information is all I've been able to obtain.

Birth data from his discharge papers is troublesome because it says he was born "in or near the town of Wicklow" in the parish of Powerscourt.

He was married to Elizabeth Pepper who was also born in the area on approximately 1782.  Any information on Elizabeth pepper and her ancestry it would also be appreciated.

He enlisted at Roundwood in 1804 at age 23. Served in 100th Regiment of Foot (later renamed 99th).  HRH The Prince Regent's County of Dublin Regiment. Regiment was in Quebec and Ontario.