This is what I have found for Peter Erasmus parents. Ancestry.ca shows him as my 3rd great grandfather.

Name Petrus Rasmus Erasmus
Birth Before 1762 Stellenbosch, Caap de Goede Hoop, Suid Afrika
Baptism Feb 28 1762
Marriage Spouse: Anna Maria Erasmus (born Klopper), a1b7c7
Nov 9 1785 Tulbagh ...