These motifs are known as Uhunmwu Ikpotoki in Edo, which translates as ‘Portuguese head’ in English. Portraits of Portuguese men, featuring only their heads and sometimes their shoulders, were used by artists as motifs on the Emwin Arhe (royal treasures), in particular on the Ama-Ẹrọnmwọn (bronze relief plaques) and Aken'ni Elao (carved altar tusks). Also included here are a series of two or three conjoined spirals, which are interpreted as abstract forms of this motif.

One of the earliest suggestions that many of the European figures depicted on objects were Portuguese was made two years after the 1897 British Colonial Military Campaign on Benin City by the British Museum curators Charles Hercules Read and Ormonde Maddock Dalton (1899, p. 19), based on testimony from seven chiefs in the aftermath of the military campaign. The long, straight hair, beards, and domed hats together led to the identification of these representations as Europeans (von Luschan 1919, pp. 54–57; Ezra 1992, p. 246).

When included within the visual imagery of the Emwin Arhe, the Portuguese are associated with the new Atlantic trade and the consequent wealth that emerged following first contact with the Portuguese in the late 15th century. For this reason, Portuguese heads are also often associated with the sea deity Olokun. Eisenhofer (2007, p. 59) argued that the Portuguese figures and heads as motifs on the royal treasures are symbols of the king’s power: “these depictions of foreigners helped to build and strengthen the king’s image.”

When incorporated into the design of the Ama-Ẹrọnmwọn (bronze relief plaques), Curnow (1997, p. 48) instead argued that these motifs could in fact indicate events that took place during Ọba Esigie’s reign. Ọba Esigie is associated with the Portuguese, as they became increasingly important during his reign, assisting with battles against the Igala from Idah, bringing Catholicism to Benin, and introducing weaponry such as guns and cannons, which were instrumental in the expansion of the kingdom.

Depictions of Ewi (mudfish) are among the most frequent motifs in the Emwin Arhe (royal treasures). Mudfish hold an important place in Edo belief, both as representations of the god Olokun and as symbols of royalty (Plankensteiner 2007, p. 410), as well as of “prosperity, peace, well-being and fertility” (Ben-Amos 1976, p. 245). Mudfish are also particularly common animals for sacrifice, and mudfish-shaped Orhiẹvbẹ (kola-nut boxes) were used to make offerings or store kola nuts.

Yet, the appearance of Ewi across the Emwin Arhe is not consistent, and it has been argued that different species of mudfish were depicted by Edo artists, each with different qualities and capabilities. For example, the electric shock of Malapterurus electricus resembles the fierceness of the Ọba, while the liminal qualities of the Synodontis clarias mudfish, which lives both on land and in water, similarly reflect the Ọba’s rule over land and sea (Gallagher 1983, p. 93). With these different qualities in mind, the mudfish is an important symbol of Benin kingship and royalty.

Sometimes the Ọba was depicted by artists with mudfish rather than legs (see Ọba with Mudfish Legs).