Admiral Niels Juel received Valdemars Slot and its Tåsinge lands in 1678, payment for the Swedish ships he had taken at the Battle of Køge Bay the year before. The house was already odd by then: Christian IV had commissioned it between 1639 and 1644, to a design by Hans van Steenwinckel the Younger, for his son Valdemar Christian — a prince who never moved in and was killed on campaign in Poland in 1656. Juel's heirs spent the following two centuries acquiring whatever land they did not already hold, until the sitting baron was the island's owner in all but name. In 1823 the population stood at 3,600, essentially all peasantry and sailors. The arrangement ended only with Lensafløsningen in 1919, when entailed estates became ordinary freehold and the baron's private court closed with them. The Juels were not merely hard landlords. They introduced apple farming, which mattered; tried industrial cloth production at a klædefabrik from 1752 to 1758, which did not; and opened public schools in 1795.

Troense sits almost directly opposite Svendborg, looking north across the sound at the town and west at Valdemars Slot. Its half-timbered houses are generously proportioned for a village of tenants, and they were not built by tenants. Sea captains and sailors raised them during the Age of Sail, when large ships were laid down on local yards and crewed for ports on the far side of the world. That money came ashore and turned into timber frames and painted infill. When the sailing trade faded, Troense found a second income in being looked at. By the end of the nineteenth century, with trains and ferries making the trip easy, visitors arrived for sea bathing and long idle afternoons, booking rooms in private pensions until much of it had quietly become a resort. The composer Rued Langgaard came; so did the writer Henri Nathansen.

Hedvig Antoinette Isabella Eleonore Jensen was twenty-one. She performed as Elvira Madigan — slack rope, trick riding, juggling, dancing — and in July 1889 she was staying in Troense with Sixten Sparre, a thirty-four-year-old Swedish cavalry lieutenant who was married. On 18 July the two walked into Nørreskov, the wood north of the village. Sparre shot her with his service revolver and killed himself the following morning. Their bodies lay undiscovered for three days. On 27 July they were buried side by side at Landet church, in the middle of the island. Tåsinge has told the story as a romance ever since, and it is worth saying plainly what happened instead: a married man killed a young woman and then himself. A granite boulder marks the spot in the forest, and Bo Widerberg's 1967 film, with its Mozart piano concerto, fixed the legend for an international audience. Visitors still leave flowers at Landet. Two people died in that wood, and only one of them was holding the revolver.

Bregninge Bakke is the island's high ground at around seventy metres, which on Tåsinge counts as a mountain. Bregninge Kirke stands on top, and from its tower on a clear day the South Funen Archipelago opens out in every direction — twenty-eight islands, sixty-five churches and twenty manor houses, says a local claim nobody seems in a hurry to audit. The church is open in the daytime, the tower deck for a modest optional fee, and the hillside around it is protected habitat. In the porch lies a Romanesque headstone over a deacon, cut with runes. Next door, Tåsinge Museum keeps the working life of the island's old sailors. A kilometre west of Valdemars Slot, beside the road, the Ambrosius Oak has been growing for some four centuries and now measures roughly seven and a half metres around. It is named for the rococo poet Ambrosius Stub — whose surname means, literally, a tree stump — who served the baron as secretary and handyman from 1739 to 1752 and is said to have sat beneath it.

Some 6,100 people live here, and they call themselves Tøsinger. The tåsingsk dialect survives, though thinner than it was. Danish national road 9 runs straight across the island, because since the 1960s Tåsinge has been a link in a chain rather than a destination at the end of a boat ride: the Svendborgsund Bridge north to Funen, the Langeland Bridge east to Langeland. Before that, ferries. The island governed itself as its own parish municipality until the 1970 reform folded it into Svendborg. Its two schools merged in 2011 into Tåsingeskolen, close to 800 pupils and the largest in the municipality. Even the name is unsettled. Scholars have argued for two centuries over whether the Knýtlinga saga's þórslundr, 'Thor's Grove', means this island or somewhere near Odense. The first unambiguous appearance is in the Danish census book of around 1231, written Thosland.