Sírlám, son of Finn mac Blatha, was, according to medieval Irish legend and historical tradition, a High King of Ireland

High King of Ireland

The High Kings of Ireland were sometimes historical and sometimes legendary figures who had, or who are claimed to have had, lordship over the whole of Ireland. Medieval and early modern Irish literature portrays an almost unbroken sequence of High Kings, ruling from Tara over a hierarchy of...

. He took power after killing his predecessor, Lugaid Íardonn

Lugaid Iardonn

Lugaid Íardonn, son of Énna Derg, was, according to medieval Irish legend and historical tradition, a High King of Ireland. His epithet, Old Irish for "dark brown", came from the colour of his hair. He succeeded his father, who had died of plague, to the throne, and ruled for nine years before he...

, in Ráth Clochair. His name means "long hand" or "long arm", and it is said his arms reached the ground when was standing up (compare the Irish god

Deity

A deity is a recognized preternatural or supernatural immortal being, who may be thought of as holy, divine, or sacred, held in high regard, and respected by believers....

 Lug

Lugh

Lug or Lugh is an Irish deity represented in mythological texts as a hero and High King of the distant past. He is known by the epithets Lámhfhada , for his skill with a spear or sling, Ildánach , Samhildánach , Lonnbeimnech and Macnia , and by the...

, whose epithet

Epithet

An epithet or byname is a descriptive term accompanying or occurring in place of a name and having entered common usage. It has various shades of meaning when applied to seemingly real or fictitious people, divinities, objects, and binomial nomenclature. It is also a descriptive title...

 lámfada also means "long arm"). He ruled for thirteen years according to the Lebor Gabála Érenn

Lebor Gabála Érenn

Lebor Gabála Érenn is the Middle Irish title of a loose collection of poems and prose narratives recounting the mythical origins and history of the Irish from the creation of the world down to the Middle Ages...

, or sixteen according to Geoffrey Keating

Geoffrey Keating

Seathrún Céitinn, known in English as Geoffrey Keating, was a 17th century Irish Roman Catholic priest, poet and historian. He was born in County Tipperary c. 1569, and died c. 1644...

 and the Four Masters

Annals of the Four Masters

The Annals of the Kingdom of Ireland or the Annals of the Four Masters are a chronicle of medieval Irish history...

. He drove Lugaid's son Eochu Uairches into exile, but after twelve years overseas Eochu returned and killed him with an arrow. The Lebor Gabála synchronises his reign with that of Artaxerxes I of Persia

Artaxerxes I of Persia

Artaxerxes I was the sixth king of kings of the Achaemenid Empire from 465 BCE to 424 BCE. He was the son of Xerxes I of Persia and Amestris, daughter of Otanes.*Artaxerxes I was the sixth king of kings of the Achaemenid Empire from 465 BCE to 424 BCE. He was the son of Xerxes I of Persia and...

 (465-424 BC). The chronology of Keating's Foras Feasa ar Éirinn dates his reign to 649-633 BC, that of the Annals of the Four Masters to 872-856 BC.