Uyu mugani bawuca iyo babonye abantu basahinda bateye imagarara, nibwo bagira bati: “Bateye rwaserera!” Uyu mugani waturutse kuri kumugabo witwaga Rwaserera w’i Rusororo mu Rukaryi (Kigali); mu mwaka wa 1700.
Icyo gihe hari ku ngoma ya Cyirima Rujugira, maze hatera inzara, kayogoza u Bwanacyambwe n’u Rukaryi n’u Buganza; abantu bo muri utwo turere bicwa n’inzara karahava. Mu Rukaryi, i Rusororo hagatura umugabo witwa Rwaserera, akaba umukungu ukomeye cyane, afite amasaka yuzuye ibigega; abantu bo muri utwo turere bakajya bamucaho inshuro, ndetse n’abafite ibimasa n’amasuka akabahahira.
Inzara igumya guca ibintu muri utwo turere. Bukeye umugabo wari utuye i Buganza bwa Shyiramuruzi witwa Rubanguka rwa Mpama arikora ajya gukeza Rwaserera. Ageze iwe, ati ” Nje kugukeza ngo unsindire iki cyago cy’inzara.”
Rwaserera aramwemerera aramuhaka amushyira mu bahinzi be. Bukeye Rwaserera ajya kureba uko abahinzi be bahinga. Ageze yo asanga Rubanguka yihagarariye.
Amubonye aramutonganya, aranamutuka cyane ati: “Dore ngo iyo nyana y’imbwa w’Umuganza w’umudeshyi ngo irandeheshereza abahinzi; nkabona iwanyu mwararimbuwe n’inzara ni ubwo bunebwe bwanyu!”
Rubanguka abyumvise ararakara, isuka ayijugunya hasi aragenda n’incuro yaciye arayita; ataha iwabo i Shyiramuruzi.
Agezeyo abitekerereza abaturanyi be, ababwira uko Rwaserera ari umugome wasagutswe n’umurengwe bikabije.
Amaze kugenda Rwaserera biramubabaza, ati ” Nta wundi muganza nzongera guhingisha cyangwa ngo muhahire.”
Kuva ubwo, uje guhakwa kwa Rwaserera akabanza kumubaza aho aturuka yamubwira ko aturuka i Buganza, akamwirukana. Abanyabuganza babura aho bahahira.
Hashize iminsi mike, Rubanguka abagisha inama yo gutera Rwaserera ngo bamunyage ubwo bukungu akangisha. Barabyanga, bati: “Nta bwo twakwiteza umuntu ejo bitazatugwa nabi mu batware cyangwa ibwami ” Abarembejwe n’inzara baremera bati: “Tuzamutera ahubwo bazatwice aho kwicwa n’inzara!”
Nuko ngo bugorobe, baboneza iy’i Rusororo ijoro ryose umuseke wa mbere utambitse bavuza induru ndende, bati: “Umwami yatanze Rwaserera!” Rubanda bakangukira hejuru, Abanyenzara bose babyumvise batanguranwa kwa Rwaserera; mbese igihugu cyose kirashika n’isahinda gitera Rwaserera!” Baramusakiza basahura ibyo yari afite byose.
Urugo baruha inkongi, ahari iwe haratikira hazize uwo mucancuro Rubanguka rwa Mpama w’i Shyiramuruzi.
Kuva ubwo rero, babona abantu benshi bari ku musozi basahinda, bakavuga ngo ” Bateye rwaserera” . Ubwo baba babagereranya n’abateye Rwaserera w’i Rusororo azize agasuzuguro n’umurengwe.
