Visualizing the differences in average ceiling heights for Diocletian's palace (4th c.), a 18-19th c. solid wall home and a modern veneer construction. I believe a drawing by Architect John Simpson. 
Diocletioan's palace (in modern Split, Croatia) was a mix between an aristocratic villa and a fortified town: it could house 9000 at 30 000 square meters.
While a Roman palace had some impressive ceiling heights, even the Roman plebs had ceilings that were at least a meter taller than modern ones: a necessity before mechanical ventilation and air conditioning.
We have the International style and the Bauhaus movement to thank for the modern 8" ceilings. All apartments or homes with taller ceilings are sold as luxury or upper class or sophisticated, which tells you what the Bauhaus crowd thought of the plebs.
John Simpson (to return to the first tweet of this thread) is a classical architect perhaps best known for the gorgeous Carhart Mansion 2007, the first load bearing masonry wall construction, and the first classical construction in Manhattan since the 1960s. Go see it if you can.
