Harold I of England, also known as Harold Harefoot, was a king who ruled from 1035 to 1040. He was the son of Cnut the Great and Aelgifu of Northumbria. Harold became king after the death of his half-brother, Harthacnut, and his reign was marked by struggles for power, particularly against his half-brother's supporters. Harold's rule was relatively short and faced challenges, including conflicts with Harthacnut's supporters in England. He died in 1040, and after his death, Harthacnut returned from Denmark to reclaim the throne, leading to a shift in power dynamics in the region.