corellianrogue for the Latin help.
The Pax Romana was a time during Rome's history when it was neither getting its butt kicked by invasions, nor was it going through civil wars. Consequently, plays on that get tossed out whenever a country goes through a long period of peace, especially if the country is a badass superpower, and has peace because it could kick its neighbors to the curb. Considering the Earth Kingdom has lasted for 100 years against the Fire Nation, it must have been pretty badass at its height.
Bumi remembered exactly where he had been when he found out the Air Nomads had been wiped out. He had been visiting Ba Sing Sei, and currently was exploring the roofs of the palace of the Earth King, when he spotted a sky bison landing. He moved closer, with the grace of an earthbender among stones, to see if it was news about Aang -- Aang was clever enough that Bumi wasn't worried about his friend, but things were less interesting without him.
Palace servants helped the airbender off the bison. "The Earth King... I need to see him." Bumi was close enough to see the burn marks on her clothing, and the way she could barely stand.
"He's meeting with the King of Omashu. We will send for him promptly."
"Tell him- Tell him that the Air Temples were attacked. The Fire Nation..." she collapsed into the arms of the servants, who bore her off as her bison bellowed its frustration at the sky.
It was on that day that the long peace that the Earth Kingdom had had, since Avatar Kyoshi defeated Chin the Conquerer, came to a fiery end. The airbender herald died during the night.