Complex sentence: Nine of her siblings died before reaching adulthood, her mother died in 1804 when Gamelin was aged 4 and her father died in 1814 when Gamelin was aged 14.
Split into simpler sentences: Nine of her siblings died before reaching adulthood. Gamelin's mother died in 1804 when Gamelin was aged 4 and her father died in 1814 when Gamelin was aged 14.