Christ" and AD means "Anno Domini", i.e. "in the year of our Lord". BBY means "before the Battle of Yavin" and ABY means "after the Battle of Yavin".
“Important Events: The Federation-Phalan War erupts between the Federation League of Planets and...AD 2574
“Important Events: While investigating two deactivated probes above Adara III, the Bantam Star is...AD 2572
“Important Events: The Roland Amendment to the Constitution of the United States of America is...AD 1985
“Important Events: After Pedrobot defeats Kolossus on the Ruby Moon of Doom and its inhabitants...AD 3001
“Important Events: The Unified Galactic Alliance is founded and integrates the Space Police.AD 2184
“Important Events: All the nations of planet Earth enter into the Exploration Pact of 4578...AD 4578
“Important Events: January 13th: Smuggler Lextor Mucron finances an illegal ten-year journey...AD 4580