Denis was one of the three sons of Ampud II, who served as ispán of Szolnok County in 1199,[1] and an unidentified daughter of Count Berthold III of Andechs, Margrave of Istria.
It is plausible they belonged to the accompaniment of Duke Andrew in Croatia and Dalmatia, who ruled the province beyond the river Drava as a de facto sovereign monarch and constantly rebelled against his elder brother King Emeric of Hungary throughout the latter's reign.
[4] The early life and career of Denis is unknown, it is plausible that he was younger than Andrew for at least a decade and raised in the ducal court in Croatia and Dalmatia.
[2] Denis was first mentioned in contemporary records in 1216, when he became Master of the treasury in the royal court of Andrew II, replacing Solomon Atyusz.
Now the center of gravity of the royal household shifts from dominions to jura regalia, and Denis transformed the system of royal economy from one based on crop management to one based on monetary income,[9] its powers are gradually extended to the whole field of financial administration and the chief executive officer rises to the rank of a national office of a purely financial nature, according to Bálint Hóman.
[8] Denis participated in the Fifth Crusade under the command of Andrew II between summer 1217 and early 1218, along with several Hungarian magnates and prelates, for instance Ladislaus Kán and Demetrius Csák.
Crossing the Jordan River, Denis led the Hungarian contingent within the crusade army in order to besiege and capture the fortress of Al-Adil I at Mount Tabor in November–December 1217, while Andrew II stayed away from the military conflict and collected Christian relics.
In his contemporary work, Arab historian Abu Shama mistakenly referred to Denis as Andrew's nephew ("the son of the king's sister"), while the Estoire d'Eracles described him as a "rich man".
[8] When they returned to Hungary, Andrew was in massive debt because of his crusade, which forced him to impose extraordinarily high taxes and debase coinage, which measures Denis directed.
[8] Few months later, the Golden Bull movement failed and Andrew restored his confidants to their formerly deprived positions, including Denis, already in the second half of the year.
[11] After Duke Coloman and his wife settled in Szepes (Spiš) region in 1222, near the Hungarian–Galician border, Andrew entrusted Denis to support him politically (it is possible he still held the dignity of ispán in the county, but there is no source for that).
There, Denis had plausibly received estates in the region, Vidernik and Savnik (present-day Vydrník and Spišský Štiavnik in Slovakia, respectively).
[23] Around that time, Archbishop Robert made a complaint about Andrew to the Roman Curia, because the king continued to employ Jews and Muslims despite his former conflict with the Holy See over the issue.
Pope Gregory IX authorized the archbishop to perform acts of religious censure to persuade Andrew to dismiss his non-Christian officials.
Historian Tibor Szőcs considers the emphasis on this was perhaps a kind of "lex Dionisii" because of Denis' previous conflicts with the church administration.
[15] During his second term as palatine, Denis usually judged over lawsuits in Transdanubia, for instance Nyitra, Pest, Sopron, Moson and Zala counties.
[25] Berend says Robert bemoaned the situation of the Catholic Church in the realm, as several clergymen lost their offices due to the presence of non-Christian financial experts.
[25] Denis was a member of that three-member diplomatic delegation – together with Simon Nagymartoni and Rembald de Voczon – to the Holy See, which the king sent for a peaceful reconciliation and to complain Robert's activity.
[6] Béla IV donated Denis' formerly confiscated estate Borica in Syrmia to the Cistercian friars of Bélakút Abbey (near present-day Petrovaradin, Serbia) in June 1237.
Therefore, historian Szabolcs de Vajay claimed Denis had a namesake son, who served as ispán of Szepes County like his father.
A certain cleric Charles, who attended the University of Bologna, was referred to as a nephew of Cardinal Stephen Báncsa in 1264, then a son of "Count Denis of Hungary" in 1269.
He argued the inscription in the tombstone of his daughter Elizabeth, where Denis was styled as "comes de Cepeз" is not necessarily identifiable with Szepes County.