In 1881, an insurrection broke out to the south of Oran province. While official correspondence and military memoirs regarded it as an outburst of religious fanaticism, we can find another proximate cause in the disastrous environmental events of the late-1870s, which conditioned social instability and multiple episodes of violence in the area. This chronology – of environmental disaster followed by insurrection against colonial authority – was an echo of an earlier episode. The disastrous decade of the 1860s, in which environmental crisis led to significant social upheaval and massive death tolls, directly contributed to the famous uprising of 1871. In each case, the colonial discourse found in official correspondence, newspapers, and memoirs of the period paid little attention to environment or climate, even though they found that nature played a large role. Indeed, colonial writers often claimed that “nature” had caused the rebellion: the “nature” of Algerians that manifested itself in such outbreaks of religiously-motivated, non-political, pre-modern violence. The purpose of this paper is to explore the relationships between violence, modernity, and nature in late nineteenth-century Algeria. The discourse that presented Algerian contestations of colonial authority as a response to and a part of “nature(s),” I argue, served to legitimize ongoing violence against Algerians. Being trapped in the “past” (unable to overcome nature – theirs or the world’s), Algerians were not capable of being modern political actors, and therefore could only engage in illegitimate violence; war was reserved for communities with legitimate political aims. Algerian anti-French violence was thus “rebellion” or “insurrection” or “revolt,” but not war. By controlling the discourse of “nature,” French colonials controlled inclusion in modernity and thus legitimate political acts. Concepts of nature – environmental nature and Algerians’ nature – contributed to the definition of modern warfare by defining what was modern and what was war. Violence against Algerians was thus naturalized as part of Algerian life. By treating these insurrections as political acts arising from the combined challenges of colonial territoriality and environmental crisis, not the “ancestral violence” of Algerians who had failed to rise above their nature(s), we can see how the complex definitions of war, violence, and modernity in nineteenth-century Algeria had roots in environmental relationships and discourses.