the Hungarians to raise their cups and drink the health of the Romans". 14th-century German chonicler Henry of Mügeln describes Denis as a "strong knight". Denis led his army advancing as far as Zimony. Denis drew his army up in three divisions in a single broad battle line, with infantry drawn up in the centre and behind the cavalry, upon which the Hungarians clearly relied for the effectiveness of their attack. On 8 July 1167, the two armies clashed near the fort along the river Sava. The Byzantines, assisted by the river fleet, achieved a decisive victory, 2,000 men were killed, while five Hungarian ispáns along with 800 soldiers were captured. Denis narrowly escaped the battlefield "with few", his shield, armor and war horse were also taken, when the Byzantine army plundered their enemy's abandoned encampment. Powerful lord Following the defeat, Stephen III signed a peace treaty renouncing the duchy – consisted of Sirmium, Croatia, Dalmatia and Bosnia – that their father had bequeathed upon his brother, Béla, who was sent to Constantinople earlier. Despite his failure, Denis retained his influence in the royal court. Three royal charters style him "comes" in the years 1171–1172. It is possible he served as ispán of Bács County, which laid at the Byzantine–Hungarian border along Lower Danube, already in 1171, although only a non-authentic charter refers to him with this title. Following the death of Stephen III in 1172, Denis, despite their previous antagonism during the Byzantine wars, supported Béla's ascension to the Hungarian throne – whose legitimacy was contested by the youngest brother Géza. Denis was appointed ispán of Bács County prior to 1177. In that year, Denis plausibly participated in the preliminary negotiations to conclude a peace treaty in Venice between Frederick I, Holy Roman Emperor and the pro-papal Lombard League. As a result of Denis' negotiations, Béla III and Frederick began to normalize bilateral relations between Hungary and the Holy Roman Empire in early 1177. After the talks, Christian, Archbishop of Mainz (Frederick's chancellor) requested Patriarch Ulrich II of Aquileia to escort Denis till the Austrian border. Emperor Manuel died in September 1180, which marked the beginning of the slow disintegration of the Byzantine Empire. Béla III reoccupied Croatia, Dalmatia and Sirmium, along with the then Venetian-controlled Zadar without combat actions at the turn of 1180 and 1181. The Hungarian king intended to reorganize the province's royal administration. Retaining his