Currently, malaria, spread via mosquitoes, is one of the major health problems in the non-Western world. Although now often associated with tropical climates, this debilitating and often deadly disease was also present in the Netherlands until the early twentieth century.

Most historical research on malaria in the Netherlands has focused on the period from the seventeenth century onwards, as historians assert that source material from before this period is scarce or even absent. Recent archaeological research, however, has provided a new insight into the history of malaria in the medieval Low Countries: according to Rachel Schats, there is skeletal evidence for the presence the disease during this period (Schats 2015).

With Schats’ findings in mind, we re-examined the source material to investigate the presence and awareness of malaria in the medieval Low Countries. Furthermore, by taking mosquito-borne malaria as our case study, we explored a new way of looking at past interactions between humans and their environment. As such, our project – focusing on hitherto undiscovered references to malaria and unexplored human-environmental interactions – revealed that which was ‘hidden in plain sight’.

Malaria in medical sources from the medieval Low Countries

Nowadays, we know that malaria is caused by single-celled parasites of the genus Plasmodium that infect the human body via mosquito bites. Once inside, the parasite invades the red blood cells, where it reproduces. After two to three days, the red blood cells burst open, releasing new malaria micro-organisms into the bloodstream. With the release of new organisms, the immune system sets to action, causing fevers, chills and muscle pain. When the parasites ‘retreat’ into new red blood cells to reproduce again, the symptoms are relieved. This life cycle causes the most important and defining symptoms of malaria, namely intermittent fevers. The bursting of the blood cells causes anaemia, which, especially in weaker individuals, such as the elderly, the sick or children, can be fatal.

In various medical sources from the medieval Low Countries, there are references to a disease with specific symptoms that we associate with malaria today. Illnesses oftentimes mentioned are vierden dach corts and derden dach curts, meaning ‘fourth-day’ and ‘third-day fever’, which are specifically differentiated from diseases like daghelexen curts, or daily fever (De Vreese 1894, 138; Braekman 1975, 101). These terms relate to the most characteristic symptom of malaria, namely fevers occurring every third or fourth day. Other terms used to describe this intermittent fever are quarteine and terciaen (Bartholomaeus Anglicus, 556, 557). The use of quarteine and terciaen had a long historical precedence. In fact, the Greek ‘father of medicine’, Hippocrates, already wrote extensively on intermittent fevers that returned every third or fourth day, and various historians have concluded that these ancient sources actually refer to malaria (Hempelmann and Krafts 2013). However, these terms were not simply copied and pasted within medieval sources, as was often the case with ancient knowledge in this period. By stating that quarteine ‘torments man on the fourth day’ and that terciaen causes fever to become more severely on the third day, they clearly connected the ancient terms quarteine and terciaen fever and the fourth- and third-day fever medical experts encountered themselves (Bartholomaeus Anglicus, 556, 557).

The medieval sources mention another characteristic symptom of malaria, namely red urine. It is stated that the urine of someone with derden dachs or vierden dachs fever is ‘red, fine and thin’ (De Vreese 1894, 116). Another source states that when a woman’s urine is the colour of rusty iron, and if she has an intermittent fever, she will die on the third day (Bartholomaeus Anglicus 1485, 555). The red urine is due to the ruptured red blood cells being filtered out through the body and ending in the urine, turning it dark red. Thus, we have two very clear symptoms of malaria described in these medieval medical sources, namely the intermittent fevers returning every three to four days and the urine turning a dark red colour. Thus, we can conclude that there is textual evidence of the presence and awareness of malaria in the medieval Low Countries.

Herbal medicine in the medieval Low Countries

Medieval people do not seem to have been aware of the connection between malaria and the presence of mosquitoes. Instead, medieval medical experts relied on the humoral theory to explain the cause of quarteine and terciaen fever. The humoral theory was the belief system that the human body was governed by four different fluids or ‘humours’ and that an imbalance between them caused diseases. As such, it is stated that quarteine and terciaen fever arise from yellow bile (one of the four humours) accumulating and building up inside the human body. This then causes heat, shivering, and muscle pain (Bartholomaeus Anglicus 1485, 555). Treatment focused on restoring the balance between the four humours through various methods, including herbal remedies.

In medieval medical sources, we find many recipes describing ways to cure malaria using various plants. Determining the extent to which the plants mentioned were available in the medieval Low Countries is difficult. Physical traces of some plants can be found in Petrus Cadé’s sixteenth-century Herbarium, the oldest known dried plant collection from the Low Countries (Cadé 1566). However, rather than focusing on availability, we used the plants mentioned in the recipes to reveal people’s interaction with the biodiversity and the environment that surrounded them.

Some herbs believed to cure quartan and tertian fever were rue, dandelion, plantain and artemisia. The recipe with rue, for example, instructs one to ‘take twenty handfuls of rue and boil it in three-fourths wine until it is one-third left.’ The patient had to drink the concoction while the fever rose (De Vreese 1894, 122). Another recipe states: ‘Against the third-day fever, take the juice of clover and three leaves of dandelion, and three leaves of plantain, and the stems of the clover. Crush this and mix it with water and drink it for three days’ (De Vreese 1894, 138). Another recipe mentions the use of artemisia, stating that ‘against the four-day fever, take the juice of artemisia, boil it and mix it with oil’, it then instructs to ‘rub your body with it’ (De Vreese 1894, 122). Interestingly, in 2015 the pharmaceutical chemist Youyou Tu won a Nobel Prize for discovering artemisia’s medicinal properties for treating malaria. Nevertheless, the World Health Organisation advises against using the herb due to concerns over resistance development and its effectiveness (World Health Organisation 2019). However, this shows that medieval herbal remedies, nowadays often seen as ineffective or working via a placebo effect, might indeed have been helpful against certain diseases.

Some of the plants mentioned in these medical sources can be found in a different medieval work, namely the sixteenth-century herbarium Cruydeboeck by Rembert Dodoens. Here, some herbs used to cure malaria are described as mosquito repellent. A notable example is the aforementioned artemisia. The Cruydeboeck states that artemisia must be mixed with oil and then applied to clothing, fabric or a mosquito net so ‘the flies, mosquitoes or mice won’t come close to it’ (Dodoens 1608, 31). Although this is an intriguing connection given our current understanding of the relationship between mosquitoes and malaria, more research is needed before making any statements about possible awareness of this connection in the Middel Ages. Nevertheless, this finding shows that medieval people were aware of the multifunctionality of the biodiversity and the environment around them.

The examples examined here are just a few of the many medical recipes we found that both mention quarteine and terciaen fever and list the various herbs believed to cure the disease.

Conclusion

By using medical sources, we examined the history of mosquito-borne malaria in the medieval Low Countries. Contrary to what some historians suggest, there is ample evidence of both the presence and awareness of malaria in the medieval Low Countries, as terms like derden dach corts, vierden dach curts, quarteine, and terciaen testify. The same medical sources provided insight into how people believed they could use various plants to cure and protect themselves against malaria. This aligns with skeletal analyses conducted by Rachel Schats, which gives strong evidence for the presence of malaria during the medieval period.

Furthermore, this research has provided a new insight into two types of human-environmental interactions in the medieval Low Countries. Firstly, the medical sources have shown how the environment and the biodiversity, namely the mosquitoes carrying the malaria parasite, interacted with society. Secondly, these sources provide insight into how people believed that the environment and the biodiversity around them could be used to combat the disease.

This research project has contributed to the history of malaria in the medieval Low Countries and offered a fresh perspective on past human-environment relationships. Thus, by using medieval medical sources, we were able to reveal insights that were ‘hidden in plain sight’.

For another contribution on the Leiden Medievalists Blog about medieval malaria, see Medieval Malaria: Skeletal evidence for this parasitic infection in the Netherlands by Rachel Schats.

-----------------------------------------------------------------------------------------------------------

The research results in this blog post stem from the Research Traineeship Program ‘Draining the Swamp Draining the Swamp: Wetlands, Insects, and Landscape Transformation in Europe, 1300-1600' conducted under the guidance of Dr. Claire Weeda and Dr. Johannes Müller.

Further reading

Primary sources

• Bartholomeus Anglicus, Van den proprieteyten der dinghen. Jacop Bellaert ed. (Haarlem 1485).
• Braekman, Willy L. ed., Middelnederlandse geneeskundige recepten (Gent 1970).
• Braekman, Willy L. ed., Medische en technische Middelnederlandse recepten. Een tweede bijdrage tot de geschiedenis van de vakliteratuur in de Nederlanden (Gent 1975).
• Cadé, Petrus, Hortus Siccus (1566).
• De Vreese, W.L. ed., Middelnederlandsche geneeskundige recepten en tractaten, zegeningen en tooverformules (Gent 1894).
• Dodoens, Rembert and Carolus Clusius, Cruydt-boeck van Rembertvs Dodonævs: volgens sijne laetste verbeteringe: met biivoegsels achter elck capittel, vvt verscheyden Cruydtbeschrijvers: item in ’t laetste een beschrijvinge vande Indiaensche gewassen, meest getrocken wt de schriften van Carolvs Clvsivs (Leiden 1608).

Secondary literature

• Boualam, MA., B. Pradines , M. Drancourt, and R. Barbieri, ‘Malaria in Europe: A Historical Perspective’, Frontiers in Medicine 8 (2021) 1-12.
• Dagen, Morag, ‘History of Malaria and its Treatment’, Antimalarial Agents: Design and Mechanism of Action (2020) 1-48.
• Knottnerus, Otto S., ‘Malaria Around the North Sea: A Survey’ in: Gerold Wefer, Wolfgang H. Berger, Karl-Ernst Behre, Eynstein Jansen ed., Climatic Development and History of the North Atlantic Realm: Hanse Conference Report (Berlin 2002) 339-353.
• Newfield, T.P, ‘Malaria and Malaria-like Disease in the Early Middle Ages’, Early Medieval Europe 25:3 (2017) 251-300.
• Schats, Rachel, ‘Malaise and Mosquitos: Osteoarchaeological Evidence for Malaria in the Medieval Netherlands’, Anelecta Praehistorica Leidensia 45 (2015) 133-140.

© Claudia Moreira Calzadilla, Nina Witteman and Leiden Medievalists Blog, 2024. Unauthorised use and/or duplication of this material without express and written permission from this site’s author and/or owner is strictly prohibited. Excerpts and links may be used, provided that full and clear credit is given to Claudia Moreira Calzadilla, Nina Witteman and Leiden Medievalists Blog with appropriate and specific direction to the original content.