When viewing the tiny, hand-coloured etchings of figures being burned alive and hair being washed in blood it is fine, the curators say, to be bemused and baffled. "They are strange," said Philippa Simpson. "Impenetrable, really, even for scholars."

The eight hand-coloured works by William Blake, an artist as bizarrely eccentric as he was visionary, are also remarkable. Today they went on display at Tate Britain in London as part of a rehang which sees nine rooms and 170 works devoted to the Romantics.

The Blakes are being displayed as part of the national collection for the first time after being acquired for the nation last year, and their history is almost as eye-catching as their content. For years their whereabouts were unknown until someone bought a box of secondhand books at a north London sale and discovered the etchings in the leaves of an old railway timetable.

That was in the 1970s, when they were thought to be facsimiles, and it took a further 15 years or so before experts fell off their chairs and declared them the real deal.

"Not only are they images by Blake but they have these handwritten lines of poetry under each one," said Simpson, who has curated the Blake display. "That is what makes them so extraordinary."

Blake, who died in 1827, was not really appreciated in his lifetime, always considered eccentric – which, as he and his wife sat naked in their garden reading Milton aloud, he probably was.

But he always tackled big and existential themes. What the themes are in the eight Blakes on display is open to long and possibly fruitless debate. One shows a man, possibly, washing his hair in a vat of blood while the flesh on his lower body appears to be melting away leaving just bones and muscles. "You might see it as a symbol of creativity," said Simpson. "But it is so complicated. You have this vegetating ball of fibrous masses which eventually will form into what Blake calls Urizen, which is a sort of strange, ambivalent God-like figure.

"It's complicated. It's probably best not to get into too much detail."

The pictures do, though, shine a light on Blake as the difficult, indefinable artist. Simpson said: "A perennial problem with Blake is that we tend to isolate him because he doesn't belong to any system or movement so he doesn't get looked at in a broader context. He's seen as an anomaly. So what I'm hoping with this display is to start teasing out connections with different artists and to show that he did not exist in a vacuum, however strange his images are."

Asked to choose a favourite – perhaps the one with the far-from-jolly caption "Vegetating in fibres of blood" – Simpson said it was instead one with an image from Blake's work The Marriage of Heaven and Hell, showing a bearded man and four robed women with the artist's handwritten words, "Who shall set the prisoners free". "It is so delicate and contemplative," she said. "You can spend a lot of time with it. For something so tiny to be so touching is amazing."

The small Blakes are displayed in a room alongside full size paintings. "I've had various sleepless nights worrying that they would be too small and not hold the space," said Simpson. "But now that they are up it's overwhelming how powerful they are for such tiny, tiny images.

"They show that being monumental is not to do with the size of your canvas, it's to do with the intensity of the image and the subjects you tackle."

The rehang is of galleries devoted to the Tate's extensive Turner collection and there is plenty of Turner on display, including a room of his early work opposite a room of his late work which includes crowd pleasers such as Norham Castle, Sunrise, and Sun Setting over a Lake.

Tate Britain curator David Brown, in charge of the rehang, said: "It's meant to give the gallery a different feel. The trouble is, everybody knows us as this great Turner collection which brings the problem of how do you keep it alive? What you don't want is a one-artist gallery that becomes a mausoleum. You need to find ways of keeping it fresh and every now and again stirring things up a bit – like the Romantics."

The new display features work by artists including John Constable and Samuel Palmer and also looks at the Romantic legacy with works by those bracketed as neo-Romantics, such as Paul Nash and Graham Sutherland.

The rehang also allows Tate to plunder its stores and show rarely exhibited works such as Edwin Landseer's A Scene at Abbotsford, the home of Sir Walter Scott, including the novelist's dying wolfhound and the expectant replacement dog in the background.

The display also includes two paintings that could be emblematic of what most people think to be the Romantics: Henry Wallis's depiction of the melancholic poet Thomas Chatterton after his suicide and William Etty's portrayal of Hero shortly after she has thrown herself on top of her beloved, but drowned, Leander.

"It's what happens if you follow the dictates of your own nature and your own self," said Brown. "You probably end up dead. We're trying to cheer people up, of course."