This article draws attention to a largely unnoticed later medieval monastic reform congregation, the French arm of the Celestine order, a Benedictine reform originally founded by the famed Abruzzo hermit St. Peter of Morrone (who became Celestine V in 1294). At first sight, the French Celestines might seem unremarkable: while they became independent from their Italian cousins in 1380, their growth pales in comparison to the reformed congregations of earlier ‘golden ages’ of monasticism: they added 20 mostly rather small houses between 1300 and 1450, and very few thereafter before their eighteenth-century suppression. Even within those recent studies of later medieval monastic reform that have begun to escape the teleology of pre-Reformation ‘decline’, they remain a footnote, seemingly dwarfed by larger contemporary Observant Benedictine reform movements in Germany and Italy. And yet, the French Celestines had an impact upon their place and time that was much greater than their numbers would suggest. This article argues that the French Celestines were one of the lynchpins of a far wider network of religious interests and actors, and one that deserves as much attention as the order itself. Firstly, it will show how they became a hub of ‘Observant’-style reform in their region: they formed part of a network of cross-order reformist interaction both in their own region and beyond, involving Carthusians, Franciscan Observants, and the Colettine reform of the Claresses, as well as other Benedictine reformers. Secondly, this article demonstrates how this network was supported by another, an intricate web of interested laity. They ranged from princely benefactors who deployed monastic reform as part of their public image, secular intellectuals who found common ideological cause, as well as pious townspeople in Northern France and Burgundy. If conflict within orders and the issue of ‘competition’ with lay piety have been important issues in recent treatments of later medieval monastic reform, this paper will re-appraise a little-known reform group by escaping such institutional boundaries and sketching the contours of a larger human and ideological network.