Original: Final Fantasy XII begins in Dalmasca's capital city of Rabanastre, where the happiness from the union of Princess Ashe of Dalmasca and Prince Rasler of Nabradia is interrupted by the Archadian Empire's invasion of Nabradia.
Simplified: Princess Ashe of Dalmasca and Prince Rasler of Nabradia were getting married, but the marriage was interrupted because Archadian Empire invaded Dalmasca.