Dublin Castle: the yards, the Beatty, two cathedrals
The castle yards, a free library of illuminated manuscripts, and the ghost line of the medieval walls. This is a Claude-drafted route awaiting the editor's walk.

1. Dublin Castle Upper Yard
Start in the big upper courtyard, the administrative heart of British rule in Ireland for seven hundred years and the place power was handed over in 1922. Walk it for free; the State Apartments are a paid tour if the morning's long enough.

2. Chester Beatty Library
Behind the castle, past the Dubhlinn Garden, one of the best small museums in Europe and entirely free — Qur'ans, Chinese jade books, illuminated gospels, all from one American mining magnate's collection. Give it an hour. The rooftop garden is a quiet bonus.

3. Christ Church Cathedral
Up the rise to the older of the two cathedrals, Hiberno-Norse foundation rebuilt by the Normans, with a vast medieval crypt — the longest in Britain or Ireland — running the full length below. The mummified cat and rat in a case down there are worth the entry alone.

4. Dublinia and the city wall
Across the covered bridge from Christ Church, the Viking-and-medieval museum, but linger outside it on St Michael's Hill — a surviving stretch of the old city wall runs here, the ghost of the line that once enclosed everything you've walked.

5. St Patrick's Cathedral
Down Patrick Street to the larger cathedral, the national one, where Jonathan Swift was dean and is buried beside Stella under the floor. The park alongside is where the holy well that named the place is said to have stood. Inside is paid; the green is free.

6. Marsh's Library
Next to St Patrick's, the oldest public library in Ireland, 1707, with the wired reading cages where scholars were once locked in with rare books. Small, perfect, often empty. From here it's a walk north to the Four Courts Luas, or back to Dame Street.

Dublin Castle: the yards, the Beatty, two cathedrals