According to Marie-Claude Dupré these masks there are known samples from as early as mid-XIIXth.

The Kidumu movement experienced an important upsurge in the decades after its invention by an iron smelter in the northwestern Tsaayi country.

Up to twenty masks appeared, coming from different regions, which competed with each other in dance (Dupré, 1991:218).

In the early twentieth century there were many immigrants to the Tsaayi region through trade, and these masks and the dances where they appeared served to solidify a diverse community and strengthen political and social bonds.

The Kidumu mask demonstrated the supernatural powers of the earth.

This system was dramatically disrupted when the French colonial powers moved into the region in the first decade of this century.

By 1920, under the civil government, only a tenth of the population survived, and the Kidumu had disappeared.
Dupré examined seventy-eight Teke masks.

The circular mask is divided into two parts at the level of the eye slits–an upper half that protrudes slightly outward and a sunken lower half–yet the overall dynamic relief pattern disguises the two levels.

Thus, this mask relies on a set of graphic design elements to convey its identity. It is certainly possible that the original prototypes for such masks were simply painted disks, as the mask bears a more "painterly" sensibility.

The raised motifs are variously named: designating a square pattern on the forehead and half moons rising from the bottom and both dominated by split-eyes that unite the two planes and various facial features with scarification or lunar crests arching along the edges. The mask and its performance are said to have originated in the mid-nineteenth century with an individual named Moukassa a Touomo, following his apprenticeship in the south of Teke country from which he arrived "with empty hands."

However, Lehuard's study of forty-three Tsaye masks suggests a strong influence from Mbamba reliquary figures. (1972:12-36)

It is also interesting to note that when you see it in front view it looks flat, but from the side the lower part  of the mask is on a low relief carving.

This example is among the finest known; the iconographic elements are bold and primal, while their juxtaposition creates a unified design. Additionally, this mask, unlike many others, displays excellent signs of age and use.

4) Another comparable Teke (Bateke) mask, painted wood, Teke tribal region, lower Congo cultural area.

In the Musee de l’Homme (quai Branly), Paris:

1) This one was collected in 1955 and published in Lehuard (Raoul), "Les arts Bateke, Congo-Gabon-Zaire", Arnouville: Arts d'Afrique Noire, 1996:114 & 117

36.5 cm  yale archive nr 0021491~01

Publication(s):  Expo cat.: "Kunsthaus Zürich-Die Kunst van Schwarz-Afrika", by Leuzinger (Elsy), Zürich, 1970:# S 1
Lehuard (Raoul), "Les arts Bateke, Congo-Gabon-Zaire", Arnouville: Arts d'Afrique Noire, 1996:114.

yale archive nr 0021492  photo:: Leuzinger, 1970 

yale archive nr 0084046~03

Expo cat.: "Remnants of Ritual, Selections from the Gelbard Collection of African Art", edited by Arthur Bourgeois and Scott Rodolitz, New York: Ethnos, 2003:32, #72 see http://www.remnantsofritual.com/gallery/072.html

Burssens (Herman) & Neerman (Marnix), "African Faces", Tielt: Lannoo, 2008:#57

photo Herman Burssens