Having been a small and quite isolated language for centuries, Siwu was relatively late to attract attention from outsiders. Europeans in search for gold to buy and people to enslave for the most part stayed near the coast. Halfway the nineteenth century, German firms (looking for cheap land) and missionary organizations (looking for converts) started to explore the Hinterland and it is in this period that the name Akpafu turns up for the first time in the historical record. (If you wonder about the etymology, see here.)

Bremen Mission Archives 7.1025-0529
The earliest mention I found so far is a photo by the German missionary photographer Christian Hornberger, titled Fetischpriester in Akpafu and dated 1864 (see below).1 Still, it took some time before Akpafu became more generally known, due in part to its remoteness, but probably also because of the turmoil caused by the Asante-British wars. Rattray’s exoticizing statement, casting Siwu as an “ancient tribal idiom”, is typical for the period and reflects the general bewilderment about the linguistic and cultural diversity of the region.
The Akpafus must immediately strike even the most casual observer as a people differing from the surrounding tribes. Their huts are flat roofed (with mud) instead of the conical grass-roofed houses of the Ewe race. Their language is not Ewe, but a remnant of some ancient tribal idiom.
Rattray 1916:431

Rudolph Plehn, Beiträge zur Völkerkunde des Togo-Gebietes (1898)
Only when the area became part of the German colony of Togoland (1884-1914), more information became available.2 The earliest ethnographic source is a study by Rudolf Plehn, published as his dissertation in Halle in 1898 and titled Beiträge zur Völkerkunde des Togo-Gebietes (Contributions to the ethnography of the Togo area). It is here that we find the oldest fragment of Siwu to appear in print, and in this posting I’ll report on an attempt to decipher it.
Continue reading- See Alsheimer (2004:160). Alsheimer cites from a letter by Hornberger: “Dass sich der Fetischpriester bewegen ließ, mir zu stehen, halte ich für einen großen Sieg, den hiermit die Photographie über den Aberglauben davon getragen. Ich stehe gegenwärtig in Unterhandlung mit etlichen Fetischweiben, und hoffe es auch bei Ihnen durch Geschenke dahin zu bringen, dass ich sie conterfeien kann.” [↩]
- A wealth of information on the colonial history of the area can be found in the Deutsches Koloniallexikon, which first appeared 1920. It has been digitized recently at the University of Frankfurt. [↩]