LASICIUS, Johannes (1531-1599). De Russorum Moscovitarum et Tartarorum ritu. Speyer: Bernardus D'Albinus, 1582. First edition, with notable Russian noble provenance, of this rare and important early source on the customs and religion of Slavic peoples. It includes, for instance, the earliest surviving printed description of various rituals, such as Ukrainian marriage and wedding customs. 4to (190 x 145mm). Woodcut device to title-page, colophon of the main text, and index. Bound in early 20th-century half vellum. Provenance: Count Grigory Alexandrovich Kushelev-Bezborodko (1832-1870) (armorial ink stamp to title); ex libris of Aleksandr Polovtsov (1832-1909), no. 2871 (calligraphic bookplate to endpaper).