Jogaila formulated the Treaty of Dubysa , which rewarded the Knights for their aid in defeating Kęstutis and Vytautas by promising Christianisation and granting them Samogitia west of the Dubysa river .
PROPN VERB DET PROPN ADP PROPN , DET VERB DET PROPN ADP PRON NOUN ADP VERB PROPN CCONJ PROPN ADP VERB PROPN CCONJ VERB PRON PROPN NOUN ADP DET PROPN NOUN .