The muqarnas of the Nasrid Alhambra stand out as one of the most singular architectural episodes o f Medieval Islamic art due to their sophisticated three-dimensional construction, whose layout remains little known. In 1834 and 1837, the architects Owen Jones and Jules Gouty visited the monument in Granada and accomplished surprising drawings thereof later published towards 1842-1845 as chromolithograph prints, which represented its architecture, ornaments, and muqarnas in a systematic way for the first time. In order to value their pioneering drawings, the historical data is briefly reviewed and several previous drawings of the Alhambra are cited. After consideration of a few questions regarding the process of data collection in Granada, a comparative analysis is presented of a cornice, a capital, an arch and a pendentive, with photos and computer-aided drawings. Thus, the principles or elementary grammar of muqarnas groupings described by these architects are highlighted, as well as the precision of their images, which resulted crucial to integrate and disseminate the architectural legacy of the Alhambra in the contemporary Western culture.