As a student, Lucas established productive relationships with English scholars and clerics like John of Salisbury. In the following decades, John of Salisbury and Walter Map became acquainted with Thomas Becket, a significant and powerful prelate in 12th-century England. Historian György Györffy compared their careers and found several similarities between the pro-papal activities of Lucas and Thomas Becket in the upcoming decades. According to Györffy, they did not know each other personally (Thomas Becket was a secretary of Theobald of Bec by the time Lucas resided in Paris), but they knew about each other through mutual acquaintances and used similar ecclesiastical tools to defend their interests against the secular royal power. As Map narrated in his anecdote about Lucas, Hugh of le Mans, Bishop of Acre informed him about Lucas' later encounters with the warring Árpád dynasty of Hungary, which Becket learned through Map.
