The Big House - also called Landshipping House - was built around 1750 by the Owen family of Orielton, who served as the local coal agents. Its stones were salvaged from an older ruined mansion further inland; even at construction, the house carried the memory of something that had failed. A 1785 estate map shows it as a modest dwelling near the river, while the Owens' grander residence, the Great House, sat a short distance away. By 1790 the Great House had been mothballed - the trustee for the young heir found, or claimed, that she could not afford to keep it open. Furniture was covered in dust sheets. Servants were dismissed. A single woman, Catherine Davies, was kept on as custodian of the closed rooms. By the time Sir John Owen inherited the estate in 1809, the Great House was roofless. So he transferred his ambitions to the smaller building near the quay - and made it bigger.

In 1830, Sir John commissioned the architect William Owen to transform the river house into something that could face Picton Castle across the water without embarrassment. Owen added a third storey to the western wing. He moved the entrance to the north facade, between two bow-fronted full-height extensions that gave the drawing rooms panoramic views over the Cleddau. Stables and servants' quarters went up at the rear. Much of the stone, it is believed, came from the crumbling Great House - one mansion dissolving into another. The design borrowed openly from Picton, the Philipps seat across the river, and from Slebech Hall. Sir John's son Hugh moved in with his wife Angelia Maria Cecilia Morgan, daughter of the Morgans of Tredegar House. The 1841 census records them at the Big House with two children and seven servants. Three years later, Angelia was dead, and so were forty of the family's miners.

The Garden Pit shaft was sixty-seven yards deep. Its galleries extended out beneath the estuary, following the Bright Vein coal seam. Above the seam, only a few feet of rock separated the miners from the river. Above that, the sand and silt of the Cleddau. The workforce that day numbered fifty-eight. Forty did not come home. The youngest victim was four years old. Four were under ten - children younger than the legal minimum set by the Coal Mines Act of 1842, which had been passed two years earlier specifically to keep them out of pits like this. Fifteen of the dead were aged ten to fifteen. Ten more were sixteen to twenty. Many shared surnames; ten belonged to the interrelated Cole and Picton families - fathers and sons, brothers, cousins. The local press barely covered the catastrophe. No complete list of names was published at the time. The village raised a memorial in 2002, more than a century and a half late. Seven of the listed dead appear only as 'Miner' - likely the women and the under-tens whose presence underground was illegal, and whose existence the official record preferred not to acknowledge.

Sir John Owen and his son Hugh were both Members of Parliament. Both seats required money. The disaster did not end the family's mining ambitions, but the cost of politics, combined with the long slow exhaustion of the seams, did. By 1857 they were forced to sell most of their holdings, Landshipping included. The auction notice described the Big House cheerfully - bedrooms, hall, parlour, dining room, drawing room, nursery, library, servants' offices, stables, coach house, walled garden, orchards, six acres of wood. It said nothing about what had happened beneath the river. The Stanley family bought the estate. Various tenants came and went. Mining was attempted again in the 1860s by John Talbot Stanley, then by John Maule Sutton, whose company collapsed in 1867. A new seam was found in 1888, but nothing was done about it. The house fell into disrepair through the late 1800s. By 1890 it was a ruin. The rear cottages stayed lived-in until the 1970s. In 1922 the whole estate was broken up and sold at auction.

In 2002, the BBC series This Land followed Alun Lewis, his partner Sarah Hoss, and their children as they moved onto the site to begin restoring the Big House. They got the second bay partially rebuilt; the roof still needed work to be weatherproof. The cameras left. The work continues, more slowly than television demands. The house stands today as a partial ruin under partial reconstruction, its bow windows still looking out over the Cleddau toward Picton Castle on the far bank - the same view Hugh Owen saw from his dining table, the same water that, on a February afternoon in 1844, took forty of his miners and never gave them back.