At least three of them, Kabojja, Busega and Seguku-Nakinzire, are situated close to the river Mayanja (see Map 1). This was the starting point of the present article. While visiting and mapping the sites, it became clear that the Mayanja river played a particular role. This water course, a "swamp river" typical of the region, has two sources: the source of the Mayanja Waswa is situated to the north of the city of Kampala, at Kawempe; that of the Mayanja Kato to the south, at Seguku. Waswa and Kato are names characteristic of masculine twins. The source of the Mayanja Kato is not far from Lake Victoria, half way between Kampala and Entebbe. It flows past Kampala, the capital (where the royal tombs of Kasubi are) and crosses the historic heart of Buganda, from south-east to north-west. About fifteen kilometres further east, the Mayanja Waswa follows a parallel course before the two branches converge at Busunju. Further on, in the borderlands of Buganda and of Bunyoro, the river flows into the Kafu, a tributary of the Nile. Many other rivers are also called Mayanja-a common name for a river-, but this one is the most important. The urban growth of Kampala is now a major threat for the Mayanja. The river is becoming more polluted and the swamps are getting filled in. A motorway linking the capital to Entebbe international airport follows the bed of the river at the entrance to Kampala.The three places of execution (Kabojja, Busega and Seguku-Nakinzire), which have been identified on the banks of the river, are located fairly close to each other, in the Kampala region. These three sites are not well documented, unlike the site of the Christian martyrs at Namugongo for which a considerable corpus of data is available. In 1886, the new King of Buganda, Mwanga, was not yet securely established on his throne: his court was splintered by intrigues and generational and religious rivalries. Concerned by the warning signs of impending colonial conquest, he launched a persecution of the Christians whose loyalty seemed to be divided between the king and the Christian missionaries. Most of the martyrs were executed at Namugongo in June 1886. Some of these martyrs were later beatified then canonised by Rome, thus becoming the first Catholic saints originating from Sub-Saharan Africa. More generally, in Uganda today, they symbolise resistance to tyranny. Much of our understanding of execution sites is derived from Namugongo. On the banks of the Mayanja, we can rely on original and complementary historical information of a different kind. Included in the dynastic history, certain myths related to the Mayanja have been preserved and provide information on these sanctuaries. In Uganda, the only other place of execution associated with a corpus of myths which has reached us is Bengo. Unfortunately, being situated outside Buganda perhaps in today's kingdom of Toro between a barracks and a refugee camp, 5 this site is very difficult to research. In any case, part of the available data on the martyrs may be extrapolated from one place to...