Ali Hassan al-Majid, 68, better known in the West as 'Chemical Ali'. He had served as a general and as defence minister in Iraq from 1991 to 1995. He was also a regional party leader.
Majid was executed about a week after he received his fourth death sentence since the fall of Saddam Hussein in 2003. He was one of the last high-profile members of Hussein's former regime still on trial in Iraq, and was executed for persecuting Iraq's Kurdish minority.
In 1988, as the Iran-Iraq war was winding down, Majid commanded a scorched-earth campaign known as Anfal to wipe out a Kurdish rebellion. An estimated 100,000 people - most of them civilians - were killed over less than a year.
The Kurds live in many parts of Iraq, but the killings took place in the north of the country. Hussein suspected the non-Arab Kurds of siding with Iran during the eight-year war.
Although Majid is believed to have been responsible for many atrocities, he was sentenced to death for his role in gassing 5,000 people in a Kurdish village. It is believed to be the deadliest chemical weapons attack ever against civilians.
Majid was hanged in Baghdad on Monday.