By using adaptation theory and Linda Hutcheon’s depiction of adapters in the process of adaptation as “first interpreters and then creators” (18), this article argues how the original Sherlock Holmes illustrations, penciled most notably by Sidney Paget, are both a canonical element of the Holmes legacy and themselves an adaptation. This creates a means of exploring why and how the television show Sherlock Holmes (1984-1994), developed by Granada Television, uses the original Holmes illustrations as a source of adaptation to create the appearance of fidelity to Arthur Conan Doyle’s Sherlock Holmes stories. Being faithful to the Holmes stories is not a common adaptation practice. Granada’s Holmes chooses to be faithful to the original illustrations and to the Victorian era, not so much to be unique among Holmes adaptations but to be similar to the 1980s heritage cinema trend of faithfully adapting English literature. Heritage cinema, as Andrew Higson states, is a “potent marketing of the past” (1), and through its propensity to adapt literature faithfully to a past time period, heritage cinema reflects a cultural desire for national nostalgia in 1980s Britain. In the case of Granada’s Holmes, this tactic turns Sherlock Holmes into both financial and cultural capital. By being seemingly faithful to the original illustrations, Granada’s Holmes is left vulnerable to the kinds of fidelity or comparative criticisms that adaptation scholars often denounce. Adaptation studies criticizes efforts to compare the source text to the adaptation, saying it will inevitably lead to privileging the source text. Through my investigation, however, I argue that there is a need to use forms of fidelity criticism in order to more fully explore the reasons why Granada’s Holmes hinges its success around fidelity to the original Holmes illustrations.