There are no theoretical texts from the Middle Ages to guide us in our reading of romances, to help us see how contemporary readers thought of the genre. But there are parodies, whole poems or momentary touches in one or another work of literature, often in romances themselves; those parodies can show us what medieval readers found most conventional in romance, and sometimes what they found most vulnerable to attack.
Over the three centuries of medieval romance in English a shift in the quantity and kind of parodies written indicates a shift in the kind of romances to which those parodies are responding. In the thirteenth century, when French literature teems with parodies of romance, there is almost nothing comparable in English, because the earliest English romances have a less conventional, more realistic content (e.g. Havelok, Horn, Bevis). As fourteenth-century romances become more and more like certain French romances, parody becomes more and more common. But the parody, far from undermining the assumptions and conventions of romance, at first supports them: comically idiosyncratic figures are eventually assimilated into the conventional court (e.g. Octavian, Percival). Then, in the hands of masters like Chaucer and the Gawain-poet, parody stretches the capacity of romance. But also with Chaucer, parody becomes more judgemental, more satirical. By the fifteenth century, it is no longer possible to incorporate parody within a serious romance: this branch of secular literature splits into very sedate, quasi-instructional romances (e.g. The Three Kings' Sons, King Ponthus), and burlesques and satires of romance (e.g. The Tournament of Tottenham, Rauf Coilzear). A sure sign that medieval romance has reached the end of its development and become a genre petrified in the past is that parody begins to strike at the way poets of old used to write, and the way only the old-fashioned or the tasteless middle-class approve now.