This paper presents the combined efforts in History, Philology and Contact Linguistics carried out by researchers from the Libolo Project, aiming the partial semi-diplomatic edition and commented analysis of the manuscript Guia de conversação portuguesa para uso dos libolos pelos missionários da Missão Católica de Calulo, by father Renato Robert (1872-1925). Dating back to 1923 and discovered in 2015, this document is an attempt to study and to record the grammar of the Libolo Kimbundu (or Bolo Kimbundu) variety spoken in the region of Libolo, Angola, whose colonization by the Portuguese settlers began at the end of the 19th century. The manuscript is also enriched with a Libolo Kimbundu vocabulary list, and it is important for the study of Contact Linguistics because: (i) it allows to confirm whether the Portuguese lexicon has already been incorporated or not into the Libolo Kimbundu right from the beginning of the colonization of Libolo region; (ii) it allows to compare grammatical structures of the contemporaneous Libolo Kimbundu, attested in speech data recently collected by the researchers of the Libolo Project, with identical structures from the beginning of the 20th century annoted in this document, in order to provide an overview about the impact of the Portuguese on the diachronic-structural evolution of the Libolo Kimbundu.