Dublin

Two settlements in one name. The Gaelic Áth Cliath was a ford of hurdles across the Liffey; the Norse longphort of 841 was built at the Duibhlinn, a dark tidal pool where the Poddle met the river. The pool lay where the gardens of Dublin Castle are now. Viking Dublin became one of the richest towns of the North Atlantic on silver and slaves, and every power in Ireland since has had to hold it.

Fish traps found when the Convention Centre was built show people fishing at the mouth of the Liffey about 6,000 years ago, and Ptolemy's map of about AD 140 may already mark a settlement here, Eblana. Before the Vikings came there was a church settlement called Duibhlinn, the black pool — a pool on the lowest stretch of the Poddle where ships moored, on the site of today's Castle Garden. The Vikings built a fortified base in 841, and under Olaf Guthfrithson in the 10th century the town became a busy trading centre, partly, some historians argue, on the slave trade. The state marks 988 as the city's founding year, and Dublin held its official millennium in 1988.

Strongbow took the city for Diarmait Mac Murchada, and Henry II came in 1171 to claim it and the lordship of Ireland. King John ordered Dublin Castle built in 1204, the first Lord Mayor was appointed in 1229, and by the end of the 13th century about 8,000 people lived here. The city held out against Robert the Bruce in 1317.

Drawn from the History section of the Wikipedia article on Dublin ↗, rewritten here and adding nothing it does not say; licensed CC BY-SA 4.0.

• St James' Church, Dublin (Church of Ireland) · holy well · 2 km
• Clondalkin · round tower · 10 km
• Mount Venus · tomb · 10 km
• Kilgobbin Cross · high cross · 11 km
• St. Fintan's Cemetery, Sutton · holy well · 12 km
• Aideen's Grave · dolmen · 12 km
• Dublin Castle · castle · under 1 km
• Baggotrath Castle · castle · 2 km
• Ashtown Castle · castle · 5 km
• Merrion Castle · castle · 5 km
• Roebuck, Dublin · castle · 6 km
• Drimnagh Castle · castle · 6 km

Straight-line distances from the town centre, from each site's documented coordinates.

• Clontarf · Good Friday 1014: Brian Boru's forces break Leinster and Dublin's Vikings — and Brian is killed praying in his tent. Now a quiet seafront suburb.
• Gleann na Smól — Oisín returns · After 300 years in Tír na nÓg, Oisín came home, touched the ground helping men lift a stone, and aged in an instant — to tell Patrick the tales of the Fianna.

All of these are pinned on the Hidden Ireland map.