How was the dome invented and what was it called? (site 2)

The dome exerts thrusts all around its perimeter, and the earliest monumental examples, such as the Roman Pantheon, required heavy supporting walls ... Byzantine architects invented a technique for raising domes on piers, permitting lighting and communication from four directions.

The answers would be dome exerts thrusts all around its perimeter, and the earliest monumental examples, such as the Roman Pantheon, required heavy supporting walls. Byzantine architects invented a technique for raising domes on piers, and communication from directions.