Hermanus was born on August 3rd, 1840 and his baptism took place on August 11th, 1840. Hermanus' father was Lucas Marthinus van Rooyen and his mother was Jacomina Aletta Potgieter. His paternal grandparents are <Unknown> and <Unknown>. He had five brothers and two sisters, named Lucas, Gert, Johan, Cornelius, Frederick, Maria and Jacomina. He was the fourth oldest of the eight children. He died at the age of 60 on August 8th, 1900.