The text is dedicated to the outstanding Polish researcher of proper names — prof. Aleksandra Cieślikowa, author and co-author of many significant monographs and onomasticons, which went beyond the limits of previous onomastic studies. The most important, selected her scientific achievements and expert activities at the Polish Language Council and the Commission on Names of Localities and Physiographic Objects were presented.

The article presents the achievements of professor Aleksandra Cieślikowa in the field of word-formation of proper names. The most important issues concerning the creation of anthroponyms in the Old Polish era selected from monographs and scientific articles are detailed. These issues include the problems of motivation in onomastic word-formation, the onimization process and the way of describing non-derivatized words by word formation and the participation of paradigmatic derivation in the emergence of Old Polish personal names. The views of Aleksandra Cieślikowa regarding Old Polish anthroponymy contributed to the development of onomastic word-formation, an integral part of the grammar of proper names and gave methodological foundations for the description of Old Polish personal names from a synchronic perspective.