The history of one morphological pattern in Swahili relative clause structure, in which the relative particle attaches to "-amba," is discussed. First, the patterns of this construction are analyzed and illustrated. The evolution of this formation from an archaic verb is then examined, noting the difficulties in tracing its history through a period of very limited written linguistic data. Patterns of "-amba" use are analyzed in three corpora of early (early 19th century) poetry and six varied modern (20th century) corpora of prose. The function of cultural and language contact in this evolution is assessed, with attention given to the influence of English in particular. A 26-item bibliography is included. (MSE)