One of the benefits of medieval literature (loosely defined as anything written between 1000-1500 CE) is that you often end up going beyond the traditional ‘literary’. I’ve noticed that a lot of scholarship done on fantasy literature is done by people who originally specialized in medieval. For example, Kathryn Hume has written both The Owl and the Nightingale: The Poem and Its Critics and Fantasy and Mimesis. Science Fiction is a bit different, since many argues it got its start during the Victorian (or later) period and scholars of those time periods or later are most likely to address it. That does not stop the occasional medievalist from getting involved. If you study medieval books though, you’re likely to come into contact with a lot of other disciplines. While this is true of other times, places, and languages, it’s especially apparent in the study of medieval Europe. If you study the medieval, you will likely run into the following in some way, shape, or form:
Classics, especially Latin: Since Latin was the main language of education and official communication for several centuries, this makes some sense. If you need to read something in its original form, and it’s official, it’ll be in Latin. On the more literary side, since Latin was a big part of education, Roman poets and theorists and philosophers were hugely influential on the Middle Ages, including Virgil, Cicero, and Ovid. Famous works of ancient Greece like Plato and Aristotle were known mostly through Latin translations (done largely by Middle Eastern scholars), and were similarly influential on literary theory, philosophy, and more.
Religion: The Church (there was only one recognized until about 1517) was a big part of medieval culture throughout Europe. Ideas and issues of faith made their way into poetry, fiction, politics, philosophy, etc. If you need to recognize what the main practices were, who key people were, how the law worked, how education was done, key philosophical practices and argumentative strategies, ad more, you need to have a reasonably good understanding of the medieval Church and faith.
History: Much like religion and faith, history relates to a lot of issues that often get brought into literature, including poetry and fiction. Political goings on often influenced culture, but also everyday life, and if you want to understand and dedication in most any work of medieval literature written by and/or for the upper classes, then you need to know the ruling families and their policies including international relationships and economics.
Science: The history of science is of course much older than the Middle Ages, but science in the modern sense was becoming more publicly recognized beyond the academy and specialist scholars between 1300-1500. If you want to read medieval poetry, a working knowledge of astronomy and astrology is useful to understand a lot of common love poetry phrases and tropes. Science also connects with history and religion, since certain practices and beliefs were sometimes at odds with traditional Church teachings. Alchemy is a medieval example, and later, Galileo and other scientists would run into trouble with Church authorities on account of scientific ideas. There is also the occasional text that includes references to botany or biology or physics or medicine as they were understood at the time.
Material Culture, such as clothing: Descriptions of what people wore, ate, or objects used in everyday life are common in many kinds of written material of the literary sort. Knowledge of clothing for example can help identify if a character is an ordained or lay member of the Church, which could have implications in the narrative. A woman’s clothing or jewelry could give an indication as to her status or her values. There’s even a poem “The Debate of the Carpenter’s Tools” which provides a major source of knowledge of how carpentry might have been done in the 14th-ish century.
Mythology and folklore: As with science, a lot of poetic and fiction tropes come from folklore and mythology. Some of the mythology is from classical sources, but much of the folklore is more localized. Being able to identify a particular character or event in folklore is often handy when trying to understand some of the more fantasy-influenced chivalric romances like Sir Gawain and the Green Knight, Lanval or Bisclavret, or Sir Orfeo. Poetry requires some similar knowledge, and extends into medicine and magic. The Middle Ages also made a lot of use of proverbs which often have folk elements or origins.
Logic: Logical reasoning and argumentation were a key part of medieval education, and as such poetry and other written works often make use of the rules of Aristotelian logic, which became popular during the 12th century. Religious poems or texts would borrow exegetical techniques which were derived from logic, dialogue was a popular argumentative and teaching tool both in fiction and non-fiction, and university staff and students often themselves were writers of poems and stories, which means that they were likely to include techniques with which they had a lot of familiarity.
Modern Cultural Theory, including gender and queer studies, and media studies: If you go to a large medieval conference that has a more multi-disciplinary focus like Kalamazoo, then you are likely to find a lot of panels that deal with the medieval in video games or films. This type of study goes back to the medievalist connections to fantasy literature, which also connects with mythology and folklore, which also connects with the history of the Church and politics, as well as elements of medieval narrative. Generic medieval Europe is a common setting for a lot of video games for example, and knowing any and all of the above noted can help in understanding some of the finer details of storytelling and world-building that area part of media studies. On the gender and identity side of things, the Middle Ages to some extent deserves its reputation for stuffiness about such things as sex but only in the official, often religious, sense. In practice, there are records of all sorts, including the literary, that suggest that gender and sexuality were in fact a lot less standardized and strictly practiced as is often presented in modern visions of the medieval.
And that’s not even going into things like bibliography, grammar, rhetoric, and art of all kinds. Knowledge all of these subjects is useful or necessary to really get into medieval literature. They are more traditionally connected with ‘literature’ but particularly for the Middle Ages also constitute a unique branch of knowledge, separate and distinct from the literary applications.