The William Shakespeare passages recited by the stage actor, are the opening and closing lines of the first speech by "Chorus" in Henry V.
The Attitude Advisor is an Elvis Presley lookalike, and almost every line he speaks contains either an exact or paraphrased line from an Elvis song.
The Pyramids count as a "granary in every city," reflecting the misconception by ancient tourists that they were grain storage buildings. They are in fact solid rock except for very small chambers for holding treasure, which were plundered not long after it was placed there, making them one of the most enduring monuments to failure in history.
Stanley Kubrick tribute: if you win the space race and then see your historical reign name, the soundtrack plays classical music pieces which were showcased in back to back Kubrick films. First is Richard Strauss' Also sprach Zarathustra, theme of 2001. Odisea del espacio (1968), followed by Ludwig van Beethoven's An die Freude, theme of Naranja mecánica (1971).
When the Medieval Military Advisor is happy, he sings "Down Among the Dead Men" by John Dyer, written in the 18th century.