Final answer:
Richard the Lionheart invaded Cyprus in 1191 during the Third Crusade, which aimed to retake Jerusalem and strengthen Christian outposts in the Middle East.
Step-by-step explanation:
Richard I of England, commonly known as Richard the Lionheart, invaded Cyprus in 1191 during the course of the Third Crusade. The intention of this crusade was to reclaim Jerusalem from Muslim control, as well as strengthen the remaining Christian outposts in the Middle East. Although the internal conflicts among the crusaders hindered progress, the capture of Cyprus was one of their significant achievements. The crusade's ultimate success was somewhat limited, but a treaty negotiated by Richard with Saladin enabled Christian pilgrims to freely visit Jerusalem, which remained under Muslim authority.