Gaelic Ireland is the name given to the period when a Gaelic political order existed in Ireland. The order continued to exist after the arrival of the Anglo-Normans (1169 AD) until about 1607 AD. For much of this period, the island was a patchwork of kingdoms of various sizes and other semi-sovereign territories known as túatha, much like the situation in Medieval Germany but in most periods without any effective national overlordship. These kingdoms and túatha very frequently competed for control of resources and thus continually grew and receded with the fortunes of time. Thousands of battles and predatory excursions involving their leaders are recorded in the Irish annals and other sources.

After the Norman invasion of 1169–71, large portions of Ireland came under the control of Norman lords – this territory was known as the Lordship of Ireland. However, the Gaelic system continued to exist in areas outside Norman control, and the government's power gradually shrank to an area known as The Pale. In 1541 the Kingdom of Ireland was established and the English monarchy began to conquer the island. This resulted in the Flight of the Earls in 1607, which marked the end of the Gaelic order.

Coordinates: 53°20′N 08°00′W / 53.333°N 8°W / 53.333; -8

Ireland (pronounced [ˈaɪrlənd] ( listen); Irish: Éire [ˈeːɾʲə] ( listen); Ulster Scots: Airlann or Airlan) is an island to the northwest of continental Europe. It is the third-largest island in Europe and the twentieth-largest island on Earth. To its east is the larger island of Great Britain, from which it is separated by the Irish Sea.

Politically, Ireland is divided between the Republic of Ireland, which covers just under five-sixths of the island, and Northern Ireland, a part of the United Kingdom, which covers the remainder and is located in the northeast of the island. The population of Ireland is approximately 6.4 million. Just under 4.6 million live in the Republic of Ireland and just under 1.8 million live in Northern Ireland.

Relatively low-lying mountains surrounding a central plain epitomise Ireland's geography with several navigable rivers extending inland. The island has lush vegetation, a product of its mild but changeable oceanic climate, which avoids extremes in temperature. Thick woodlands covered the island until the 17th century. Today, it is one of the most deforested areas in Europe. There are twenty-six extant mammal species native to Ireland.

The Irish people (Irish: Muintir na hÉireann or na hÉireannaigh; Ulster-Scots: Airisch or Airish fowk) are an ethnic group who originate in Ireland, an island in northwestern Europe. Ireland has been populated for around 9,000 years (according to archaeological studies, see Prehistoric Ireland). The Irish people's earliest ancestors are recorded in legends – they are claimed to be descended from groups such as the Nemedians, Fomorians, Fir Bolg, Tuatha Dé Danann and the Milesians.Lebor Gabála Érenn, a book of Irish mythology tells that Tuatha Dé Dananns were Scythian descendants.

The main groups that interacted with the Irish in the Middle Ages include the Picts, Scots, and the Vikings. Due to this contact, Icelanders are noted for having some Irish descent. The Anglo-Norman invasion of the High Middle Ages, the English plantations and the subsequent English rule of the country introduced the Normans and Flemish into Ireland. Welsh, Picts, Bretons, and small parties of Gauls and even Anglo-Saxons are known in Ireland from much earlier times.