The Battle of Magh Tuireadh is, confusingly, the title of not one, but two medieval Irish prose narratives which relate the history of the Tuatha Dé Danann, the immortal and magically gifted people that, according to Irish Mythology, ruled Ireland before the coming of the Gaels.
The First Battle of Magh Tuireadh: The Tuatha Dé Danann arrive in Ireland from an unknown place of origin, intending to settle there. The present inhabitants of the country, the Fir Bolg, refuse to give up one half of the island and opt to fight for the whole instead. In a four-day battle at Magh Tuireadhpronunc. , the Plain of Pillars (a.k.a. the Magh Tuireadh at Cong or the Southern Magh Tuireadh), the Fir Bolg are devastated, but in honor of their valour the Tuatha Dé let them have a quarter of Ireland, Connacht.
However, the king of the Tuatha Dé, Nuada, has lost an arm in the battle, and according to the laws of the Tuatha De has to abdicate the throne, and Bres, a noble renowned for his beauty, is made king instead.
The Second Battle of Magh Tuireadh: Meet the Fomor, a fierce people of sea-faring giants. The Fir Bolg paid tribute to them, but now that the Fir Bolg are defeated, the Tuatha Dé face the same demand. King Bres seeks the friendship of the Fomoire, and to raise their tribute, imposes high taxes on the Tuatha Dé, forcing them to do lowly work. Thus it is no wonder that when, after seven years, the physician Miach succeeds in restoring Nuada's arm, the Tuatha Dé at once depose Bres and make Nuada king again.
Craving revenge, Bres, who, as it turns out, is actually the son of the Fomorian Elatha, sails to the land of the Fomoire, Lochlann, and spurs them on to invade Ireland. This means preaching to the converted with his father, who, while he admonishes his son, sends him on to Balor of the Evil Eye.
Back in Ireland, a newcomer, Lugh, fosterling of Manannan, arrives at Nuada's court. The guards almost send the youngster away, but eventually his talents convince Nuada that Lugh is just the right man that can beat the Fomor, and makes him commander of the Tuatha Dé armies.
Having spent years preparing for war, the two peoples clash at the Second Battle of Magh Tuireadh (a.k.a. The Northern Magh Tuireadh), in an ultimate showdown that will prove costly for both sides.
Provides examples of the following tropes:
- Artificial Limbs: After Nuada has lost one arm in battle, the physician Diancecht makes an artificial arm of silver for him.
- Badass Army: The army of the Tuatha de Danaan at the Second Battle. At one point, each named character lists what they will do in the coming battle, such as hurling mountains against the Fomor, and filling their men with such strength they could fight for seven years without rest.
- Balloon Belly: The Dagda, in one memorable sequence involving porridge during the Second Battle. It doesn't stop him from...giving Indech's daughter a piggy back ride.
- Big Badass Battle Sequence: The First and the Second Battle of Magh Tuireadh.
- Burning the Ships: The Tuatha Dé Danann burn their ships upon landing in Ireland to challenge the Fir Bolg for one half of the island.As for the Tuatha Dé Danann, they all arrived in Ireland, and immediately broke and burnt all their ships and boats.
- The Big Guy: Sreng is repeatedly described as large and intimidating. Invoked by the Fir Bolg, who select him to meet with Bres specifically for that very reason.
- The Chosen One: Lugh of the Long Hand. Despite he is only a youngster, Nuada gives him the command of the Tuatha Dé armies. Apparently he believes Lugh is destined by fate to defeat the Fomor.
- Disappeared Dad: Elatha isn't a hands-on father, to say the least.
- The Dog Bites Back: In the second battle, the Fir Bolgs go to the Fomoire after the Tuatha Dé subjugate them.
- Even Bad Men Love Their Mamas: Bres' closest relationship in the text is with his mother, Eriu, who goes with him to meet his father and patch things up. Modern viewers may not realize that this is actually one MORE sign of his badness, since it makes him more dependent on the women of the tribe than the men.
- Eye Beams: Balor's Evil Eye burns anything he looks at.
- Instant Seduction: It...does not take too long for Elatha to...endear himself to Eriu, which produces Bres.
- Luke, You Are My Father: Technically, Eriu does the introducing, but otherwise Bres' introduction to Elatha's a textbook example. Played with in the sense that Elatha knew perfectly well that he had a son named Bres who was with the Tuatha dé, he just didn't realize that HE was Bres.
- Magical Eye: King Balor's. It kills anyone he looks at.
- Person of Mass Destruction: Balor of the Evil Eye, whose eye, when opened, destroyed whole troops of warriors standing before him.
- Plot-Relevant Age-Up: Bres grows at twice the rate of normal kids until he's a 14 year old.
- Sacred Hospitality: Flouted by Bres, who not only refused to feed and shelter the Tuatha De properly during his stint as king, but puts a number of them to servant work and humiliates them as well.
- Small Role, Big Impact: Sreng mac Sengann only appears in person during the first battle, where he takes a big role for the Fir Bolg side, but among a ton of other characters, and then he's totally absent from the second save for a single mention, and yet literally everything that happens afterwards is because of him.
- Suffer the Slings: Lugh finally kills Balor with a stone from a sling, which hits Balor so hard it knocks his eye all the way through his crushed head.
- Talking Weapon: Orna, sword of the Fomorian king Tethra, which, when taken out of its sheath, "told all the deeds that had been done by it, for there used to be that power in swords."