Complex sentence: Sarie was a legendary Voortrekker woman who died, aged 37, with the birth of her 11th child and is immortalised by the eponymous song, an indelible part of South African culture.
Split into simpler sentences: Sarie was a famous Voortrekker woman who died, aged 37, having her 11th child. She is immortalised by the song of the same name, now indelible part of South African culture.