[2] Early in life, he was often held as a pledge for his father and later his brothers good conduct to both the English and to important Irish dynasties.
Collectively, the ten brothers were known as the "Mac Shanes" and waged continual war from 1583 to 1591 for domination of Ulster with the backing of a Scottish army made up of MacLeans and MacDonnells.
[7] However, he was overthrown and during the 9 Years War, he was arrested and again held captive by his cousin on an island stronghold in Killetra.
When the Earl fled Ireland in 1607, Conn was rewarded with a large estate known at Clabbye in south-western Ulster for the rest of life.
[10] To that fact, in 1683, Conn's grandson Cormac MacShane O'Neill traveled to Spain and unsuccessfully petitioned for the title and position as the 8th Earl/Count of Tyrone in the Spanish creation.