Final answer:
Richard I of England joined Philip II of France in Acre during the Third Crusade, with historical records indicating Richard's arrival in June 1191. Together they conducted military operations, including the siege of Acre, although their alliance was not without tensions.
Step-by-step explanation:
Philip II of France and Richard I of England were prominent figures during the Third Crusade, which lasted from 1189 to 1192. This crusade was initiated in response to the fear of losing Outremer and the desire to retake Jerusalem after Saladin's successful reclaiming of the city in 1187. The arrival of the European kings, including Richard the Lionhearted, at the Christian outposts led to internal divisions, but they managed to secure some territory.
Though there was infighting, Richard I, known for his valor as Richard the Lionheart, negotiated a treaty with Saladin. The specifics of Richard joining Philip in Acre are not directly detailed within the provided references, but both rulers were key participants in the Third Crusade's efforts in that area.
Historical accounts suggest that Richard and his forces arrived in Acre in June 1191 after Philip's arrival. Their collaboration was marked by military operations against the Muslim forces, including the siege and eventual capture of Acre. However, after Acre, the relationship between Philip and Richard began to deteriorate due to differing interests and tensions over the control of territories won during the Crusades.