Science fiction was first codified in the 1920s by Hugo Gernsback, but he was building on a legacy that went back more than a century. Gernsback cited HG Wells, Jules Verne, and Edgar Allen Poe as prior examples of the genre, even though only Wells would live long enough to actually hear the term in use (and even then, I can find no evidence of his thoughts on the matter).

Clearly, these authors were unaware of science fiction, but one term that would have been familiar is scientific romance. To be clear, this is not the SF equivalent of the romantasy that dominates today’s market. The romance here means an adventure, a sense of excitement and usually some action. oftentimes a journey is included.

What was scientific about it? I hear you ask. Well, this was the nineteenth century, when scientific literacy was on the rise, and it was growing increasingly easy for young men to have an education. This had two linked effects. Firstly, writers could include scientific details without alienating their audience. Secondly, readers were hungry for the science behind their flights of fancy. It was no longer sufficient to use magical reasoning to justify wondrous events. People didn’t just care about what was happening, but how it was happening.

The great pioneer of scientific romance was Jules Verne. One need only look at his 1865 novel Seven Weeks in a Balloon to see the foundations of his work. Here he details the extraordinary mathematics that goes into the workings of a hot air balloon, while also exploring the geography of Africa. Two years later, Verne travelled further still with Journey to the Centre of the Earth. The Hollow Earth theory had already been thoroughly debunked by Verne’s time, but Verne took a meticulous approach to geography to justify his subterranean fiction.

In 1868, Verne travelled further still, this time From the Earth to the Moon. His inventive depiction of a human crew launched into space by a vast cannon is ridiculous to modern eyes, but was plausible based on science as understood at the time of publication. Verne returned to this idea with 1872’s Around the Moon, which further details the perils of spaceflight, and a realistic depiction of the lunar environment.

Between this lunar voyages, Verne wrote 20,000 Leagues Under the Sea. A more straightforward adventure novel, it nevertheless features a very early vision of the electric submarine – one that still holds up today.

A decade later, another author entered the game 1884’s Flatland is not strictly scientific romance, but rather a mathematical one. Edwin Abbott Abbott crafts an utterly unique world inhabited by two-dimensional creatures. As with many novels of the time, Flatland is in no small part a satire of then-present day society, but for our purposes it is more noteworthy for the amount of time spent explaining mathematical concepts. Understanding of maths does not change so frequently as that of science, thus much of the novel still holds true.

Jules Verne books continued into the early twentieth century, but by the end of his career, the Frenchman’s star had been eclipsed by the new forerunner of scientific romance. HG Wells arrived on the scene in 1895 with The Time Machine, the first of several great novels. In many ways Wells was a mirror to Verne. He too employed science to send his characters on grand adventures, and to examine society. That science was often explained in detail. The key difference is that Wells was happy to invent new branches of science fiction, rather than simply staying abreast of current discoveries.

1898’s The War of the Worlds is perhaps the strongest example of this. Taking into account all that was known about Mars, Wells imagined what manner of creature might inhabit the Red Planet. Her did not believe such creatures to actually exist, but was eager to pit them against humanity to examine the cost of a war on British soil. Like Verne, Wells sent men to the lunar surface in 1901’s The First Men in the Moon. Not with a cannon, but with a metal which defied gravity, and could not exist according to science. Wells’ Moon was as inhabited as Mars, with creatures similarly designed for their harsh environs. Wells soon turned his attention to changes in society and visions of the future, but his place in the canon was secured.

Edgar Rice Burroughs took Wells’ looser approach to science and ran with it. 1912’s Princess of Mars and its many sequels transported US Civil War soldier John Carter to a fantastic version of mars, peopled by innumerable cultures and species, with a breathable atmosphere and warriors boasting powers of the mind. Carter did not travel by rocket, cannon, or strange metal, but by dreaming himself to be there. Burroughs had little concern for science, leading to an offshoot genre generally called ‘planetary romance’ or ‘sword and planet.’ His action-first approach (including a healthy dose or romance in its more common usage) were immensely popular in the pulp magazines of the time. Later, Burroughs would write similarly bold adventures set on Venus, beneath the Earth’s surface, and in the jungle home of his most famous creation: the wild man Tarzan.

Scientific romance as a unique genre fell into obscurity over the First World War, as the threats posed by modern technology came to be as evident as its wonders. One of the final gasps of the genre was 1920’s A Voyage to Arcturus by David Lindsay. Lindsay’s premise is similar to Burroughs, with a lone human travelling to an alien world, but his approach is more melancholy, and deeply entrenched in the parallel genres of the gothic and the weird. Some of Lindsay’s ideas, alongside those of Wells and Burroughs, would be recycled and pushed further into the realms of the scientifically amazing in the latter half of the 1920s, as the successor genre of space opera was born.

Scientific romance still has its echoes today, perhaps most notably in the works of Stephen Baxter. The Hard SF we say to day is in many ways the latest incarnation of that centuries-old tradition. Top couple science with adventure. It may not always be recognisable as such, but scientific romance still persists in the DNA of science fiction, and will likely remain entwined there for a long time yet.