Achilles developed a relationship with Braiseis and planned to marry her upon his return to Greece. However, King Agamemnon angered Achilles when he took his fiancé away. Achilles refused to fight for Agamemnon and the Greeks against the Trojans. This tantrum became the famous "rage and wrath of Achilles". 

Finally, after Hector, the Trojan prince and brother of Paris killed Achilles' cousin Patroclus, Achilles joined the battle. Despite heroic feats, he was doomed when an arrow shot by Paris mortally wounded Achilles in his ankle - his only vulnerable spot. 

Achilles, the greatest of Greek warriors died before he was able to marry Braiseis.

The 2004 movie "Troy"  featured Brad Pitt as Achilles and Rose Byrne as Braiseis.