 Oberkassel was first mentioned as "Cassele" in 722/723 and as "Cassela" in 1144.The name "Oberkassel" refers to a Roman fortification; in the course of time "Romerkastell" (Roman castle) became "Oberkassel".Oberkassel absorbed the previously separate settlements of Berghoven (mentioned for the first time in 873), Büchel (mentioned for the first time in 1202), Broich (mentioned for the first time in 1306) and Meerhausen (mentioned for the first time in 1442).