St Joseph's Cathedral, and the pagoda that stood there first

St Joseph's Cathedral is the oldest church in Hanoi and the most weathered building in the centre of it. Twin towers of grey stone, about 31 m tall, rise at the end of a short street the city treats as a living room.

The cathedral opened in 1886, which makes it one of the first things the French built here. What stood on the ground before that is the part worth knowing.

What was on the site first?

Bao Thien pagoda stood here first, founded in the 11th century under the Ly dynasty, with a tower that ranked among the great monuments of early Thang Long. By the 19th century it had long been ruined, and the site was cleared for the cathedral.

The sequence is not a footnote in Hanoi. A colonial church on the ground of a Ly foundation reads here as exactly what it looks like. The imperial citadel a few streets away is the other half of the same story.

Why does it look like Notre-Dame?

Because it was meant to. The design is neo-Gothic, with twin square towers, a rose window and ribbed vaults. The resemblance to Notre-Dame de Paris is deliberate rather than accidental.

The execution is colonial-budget rather than Parisian. The walls are rendered and stone-coloured rather than stone, and the detailing is simplified. A century of Hanoi weather has blackened the whole thing to the grey in the photograph, which most visitors prefer to new.

When can you go in?

Between services, through the side door on Nha Chung street when the main doors are shut. The interior runs darker than the square outside suggests. Stained glass from the 1890s, a vaulted nave, and an altar in gilt and red lacquer that is more Vietnamese than the exterior prepares you for.

Dress as you would for a working church, which is the same standard the pagodas guide sets out for temples: shoulders and knees covered, phones down during a service.

Is it a tourist site or a parish?

The cathedral is a parish first, and the congregation is the reason it feels different from the rest of the Old Quarter. Vietnam has one of the larger Catholic populations in Asia, somewhere around 7 per cent of the country. St Joseph's Cathedral is where that community gathers in the capital.

Sunday evening is when that is most obvious. The square fills with families, the doors stand open, and the singing carries out over the tea stalls across the road. The religions guide sets that in the context of everything else Vietnam believes.

What is the tea corner?

Tra chanh on the pavement, and it is half the reason to come here. The corner of Nha Tho street facing the cathedral is the best-known iced-lemon-tea spot in Hanoi. Plastic stools spill into the road and a glass costs 15,000 to 25,000 dong.

Arrive around 17:00 and the corner is full of students. The corner is one of the few places in the city where visitors and Hanoians sit on the same stools doing the same thing. The pavements guide explains that better than any list of sights.

What happens here at Christmas?

Christmas Eve turns the square into the busiest open space in Hanoi. Thousands arrive, most of them not Catholic, for the lights, the photographs and the crowd rather than for midnight mass. The police close the surrounding streets.

Anybody in the city on 24 December should walk past once and not try to get inside. The festivals guide covers the rest of the calendar, including the ones that empty the city rather than filling it.

How does it fit a walk?

The cathedral is 10 minutes west of Hoan Kiem lake and marks the edge of the Old Quarter. Ten minutes inside, 10 on the square and a glass of tea still leaves you a short walk from everything else in central Hanoi.

Pair St Joseph's Cathedral with the colonial buildings along the way rather than with another temple. The colonial architecture guide maps what survives of that period and what has come down in the last twenty years.