Complex sentence: Alphonse de Polignac (1826--1863) was a French mathematician whose father, Jules de Polignac (1780-1847) was prime minister of Charles X until the Bourbon dynasty was overthrown (1830).
Split into simpler sentences: Alphonse de Polignac (1826--1863) was a French mathematician. His father, Jules de Polignac (1780-1847) was prime minister of Charles X until the Bourbon dynasty was overthrown (1830).