The fillet, a handmade fibrous band, was a personal accessory of day-to-day rituals in antiquity. This thesis examines the design, fabrication, and sacral applications of fillets in ancient cult practice (c. 8th century BCE-4th century CE). “Fillet” is derived from the French, fil, which in turn comes from the Latin, filum, meaning “thread.” Ribbons, headbands, belts, and like accessories generated bonds of ritual contact when they adorned the agents and spaces of sacred rites. These bands were forms of κόσμος, a Greek term designating embellishment that reflected the world’s divine organization, and from which is derived our senses of “cosmos” and “cosmetic.” By crafting bands, fillet-handlers constructed their ritual environments. Examining the archaeological record, inscriptions, and literary sources, my research adopts a transregional scope while contextualizing local perspectives. Fillets were constructed through a number of fiber-working techniques, but they were regularly remade in ritual gestures. I examine how their verbal and visual representations attest to their sustained relevance. Fiber crafts, I argue, presented alternative systems of aesthetic value, in which long-ignored agents of cultural production—everyday materials, the labor of the marginalized—were central.