Complex sentence: Grand Dukes of Luxembourg after William III of the Netherlands ruled separately as an independent country after the personal union with the Netherlands ended in 1890, making Adolphe, Grand Duke of Luxembourg, the first independent Grand Duke of Luxembourg.
Split into simpler sentences: Grand Dukes of Luxembourg after william III of the Netherlands ruled seperately as an independent country after the personal union with the Netherlands ended in 1890. Making Adolphe, Grand Duke of Luxembourg, the 1st independent Grand Duke of Luxembourg.