Erazm Rykaczewski’s Dokładny słownik polsko-angielski… (1851) was the first Polish- English dictionary. As well as English equivalents for Polish headwords, it offered a rich selection of Polish illustrative examples paired with their English counterparts to provide the user with information on the way the headwords are used in context. While making a bilingual dictionary requires fluency in both languages, Rykaczewski’s knowledge of English was somewhat less than perfect. In the light of the above, how he compiled the volume’s English side remains largely unresolved. This paper empirically tests the hypothesis that he drew on the works of other lexicographers. The research methodology was twofold. Firstly, Fleming and Tibbins’s Royal dictionary (1844-1845) was examined to ascertain whether it formed a part of Rykaczewski’s background material and, if so, to what extent. Secondly, English examples of usage unrecorded in the Royal dictionary were verified against Google Books, a gigantic corpus of texts, to identify potential sources.