Final answer:
Guardian figures at important sites were usually hybrids of humans and animals, known as Lamassu, taking the form of human-headed winged lions. These powerful protectors symbolized the might of the Assyrian king and served as both aesthetic and protective features of ancient citadels.
Step-by-step explanation:
The guardian figures that usually protected the entrances to important sites were hybrids of humans and animals, typically represented as Lamassu. These guardians were human-headed winged lions, often carved in stone, standing vigil at the gates of palaces and important buildings in the Assyrian empire.
Such mythological figures can be traced back to ancient Sumer and have been found guarding the palace of Persepolis. They not only served as guardians at the entrances but were also symbolic of the fortified nature of citadels, which were designed to protect the inhabitants and core structures such as the temple and the royal palace in times of warfare.