Parish registers:
Parish Registers are records of baptisms, marriages, and burials made by the Church. Parish Registers are an invaluable resource for researching your family tree because the census and official records of birth, marriage and death do not go back further than 1837. Parish records can considerably extend your research because most records go back to the 17th century, and some even go back as far as the 1500s.
primogenitor:
the earliest known ancestor or forefather.
primogeniture:
a right of inheritance of the eldest son (or the senior living male relative) to inherit the estate of both parents, to the exclusion of younger siblings. From the Latin for "first-born".