Lucas I is the earliest known member of the gens Péc, which had large-scale possessions in several counties of Transdanubia, in addition to other parts of the Kingdom of Hungary. They originated from Sokoró Hills, their ancient clan estate laid in present-day Felpéc and Kajárpéc. Based on the clan's coat-of-arms, it is possible that Lucas was a knight from Western Europe, who arrived to Hungary during the early reign of Andrew II of Hungary. For his military service, he was granted lands in Győr County and the surrounding regions. Lucas I had three sons: George served as ispán of Zala County from 1243 to 1244; Mark I, who was forefather of the Marcali, Berzencei and Szentgyörgyi noble families; and Lucas II.
Identification
There is a scholarly debate on the difficulty of the identification of Hungarian nobles with the given name "Lucas", who were active in the 1230s. 19th-century historian Mór Wertner considered all of them as a single person in his various academic works, albeit with various sturdiness. He claimed that all of relevant data refer to a certain Lucas, son of Hippolytus, who is mentioned by a charter in 1206. Wertner connected this individual to the Péc kindred. Subsequently, he slightly modified his viewpoint, and considered Lucas, who functioned as ispán of Hont County, was "probably different person". Historian Attila Zsoldos analyzed further the question: he separated Lucas, the ispán of the Bakony royal forest too, as its office-holders came from a lower social status in the era. Furthermore, as Zsoldos denoted, the ispán of Moson County was certainly different person from the ispán of HontCounty, as they both appeared in the same royal charter in 1239. Attila Zsoldos then considered, there were four different office-bearer nobles with the given name Lucas in the first third of the 13th century:
Lucas, who belonged to the court of King Andrew II. He served as Master of the cupbearers from 1229 to 1230, beside his position of ispán of Bars County. Possibly he is identical with that Lucas, who briefly functioned as ispán of Pozsony County in 1235. Several historians, including Attila Zsoldos and Tamás Kádár considered this baron might be identical with Lucas I Péc, who rose to the Hungarian elite during his decades of service in the court of Andrew II, but rapidly lost political influence, when Béla IV of Hungary ascended the Hungarian throne in 1235.
Lucas, who was a confidant of Duke Béla, who had long opposed his father's land grants and policy. He was Ban of Severin in 1233, following his predecessor Buzád Hahót's retirement. After Béla's coronation as Hungarian king, he served as ispán of Moson County between 1235 and 1240. It is plausible he was killed during the First Mongol invasion of Hungary.
Lucas, who came from a lower social status, and functioned as count of the Bakony royal forest from 1232 to 1233.
Lucas, who was ispán of Hont County from 1237 to 1239. It is possible that he is identical with #1 Lucas, who was forced to be satisfied with this relatively insignificant position after Béla IV's enthronement.
