Manslaughter
Manslaughter is a relatively new legal concept. It was first mentioned in an English statute in 1547, but was interpreted very loosely and not earnestly enforced, instead usually charging with murder.  Very few countries had manslaughter on their books until the latter half of the 20th century.  In fact, no jurisdiction in the United States had manslaughter on its books until the 20th century.  England and the United States were the first two countries to introduce manslaughter into their laws.