Cath Maige Tuired in the context of "Tuatha Dé Danann"

Irish mythology is the body of myths indigenous to the island of Ireland. It was originally passed down orally in the prehistoric era. In the early medieval era, myths were written down by Christian scribes, who Christianized them to some extent. Irish mythology is the best-preserved branch of Celtic mythology.

The myths are conventionally grouped into 'cycles'. The Mythological Cycle consists of tales and poems about the god-like Tuatha Dé Danann, who are based on Ireland's pagan deities, and other mythical races like the Fomorians. Important works in the cycle are the Lebor Gabála Érenn ("Book of Invasions"), a legendary history of Ireland, the Cath Maige Tuired ("Battle of Moytura"), and the Aided Chlainne Lir ("Children of Lir"). The Ulster Cycle consists of heroic legends relating to the Ulaid, the most important of which is the epic Táin Bó Cúailnge ("Cattle Raid of Cooley"). The Fenian Cycle focuses on the exploits of the mythical hero Finn and his warrior band the Fianna, including the lengthy Acallam na Senórach ("Tales of the Elders"). The Cycles of the Kings comprises legends about historical and semi-historical kings of Ireland (such as Buile Shuibhne, "The Madness of King Sweeny"), and tales about the origins of dynasties and peoples.

Lugh or Lug (Old Irish: [l̪uɣ]; modern Irish: Lú [l̪ˠuː]) is a figure in Irish mythology. A member of the Tuatha Dé Danann, a group of supernatural beings, Lugh is portrayed as a warrior, a king, a master craftsman and a saviour. He is associated with skill and mastery in multiple disciplines, including the arts. Lugh also has associations with oaths, truth, and the law, and therefore with rightful kingship. He is also associated with intelligence. Lugh is linked with the harvest festival of Lughnasadh, which bears his name. His most common epithets are Lámfada (Modern Irish: Lámhfhada [ˈl̪ˠaːw ad̪ˠə]; "long hand" or "long arm", possibly for his skill with a spear or his ability as a ruler) and Samildánach (Modern Irish: Samhaildánach [ˈsˠawəlʲ d̪ˠaːnˠəx]; "equally skilled in many arts"). This has sometimes been anglicised as "Lew of the Long Hand".

In mythology, Lugh is the son of Cian and Ethniu (or Ethliu). He is the maternal grandson of the Fomorian tyrant Balor, whom Lugh kills in the Battle of Mag Tuired. Lugh's son is the hero Cú Chulainn, who is believed to be an incarnation of Lugh.

The Mythological Cycle is a conventional grouping within Irish mythology. It consists of tales and poems about the god-like Tuatha Dé Danann, who are based on Ireland's pagan deities, and other mythical races such as the Fomorians and the Fir Bolg. It is one of the four main story 'cycles' of early Irish myth and legend, along with the Ulster Cycle, the Fianna Cycle and the Cycles of the Kings. The name "Mythological Cycle" seems to have gained currency with Arbois de Jubainville c. 1881–1883. James MacKillop says the term is now "somewhat awkward", and John T. Koch notes it is "potentially misleading, in that the narratives in question represent only a small part of extant Irish mythology". He prefers T Ó Cathasaigh's name, Cycle of the Gods. Important works in the cycle are the Lebor Gabála Érenn ("Book of Invasions"), the Cath Maige Tuired ("Battle of Moytura"), the Aided Chlainne Lir ("Children of Lir") and Tochmarc Étaíne ("The Wooing of Étaín").

The Fomorians or Fomori (Old Irish: Fomóire, Modern Irish: Fomhóraigh / Fomóraigh) are a supernatural race in Irish mythology, who are often portrayed as hostile and monstrous beings. Originally they were said to come from under the sea or the earth. Later, they were portrayed as sea raiders and giants. They are enemies of Ireland's first settlers and opponents of the Tuatha Dé Danann, the other supernatural race in Irish mythology; although some members of the two races have offspring. The Tuath Dé defeat the Fomorians in the Battle of Mag Tuired. This has been likened to other Indo-European myths of a war between gods, such as the Æsir and Vanir in Norse mythology, the Olympians and Titans in Greek mythology, and the Devas and Asuras in Indian mythology.

One theory is that the Fomorians were supernatural beings representing the wild or destructive powers of nature; personifications of chaos, darkness, death, blight and drought.