Humans began eating oatmeal for breakfast thousands of years ago – most commonly in the British Isles – so it’s impossible to know who “invented” it. However, a guy named Conor, who lived near the current town of Dunfanaghy on the Donegal coast around 420 BC is said to be the inventor of oatmeal.
Quaker oats were however, invented on 4 September 1877 by the Quaker Mill Company of Ravenna, Ohio, United States, which held the trademark on the Quaker name and was acquired in 1901 by Henry Parsons Crowell, who In the 1850s, Ferdinand Schumacher and Robert Stuart founded oat mills.