Final answer:
Prince Shōoku built the Temple of the Four Guardians to promote Buddhism and express the centrality of the monarch's power, integrating both political and religious messages in the architecture and iconography.
Step-by-step explanation:
Prince Shōoku built the Hōryūj-ji temple, often referred to as the Temple of the Four Guardians, as a way to adopt and promote Buddhism in Japan. During the 7th century, Buddhism played an essential role in consolidating the central authority of the monarch and was seen as a means to express the ruler's power and legitimacy. The construction of grand temples was a direct reflection of the political and religious aspirations of the period and was also used to subsume Shinto gods, thereby integrating religious and political messages. For example, the Tōdaiji temple complex, built later by Emperor Shōmu, housed a grand gilded bronze Buddha that not only signified the emperor's power but also included a small shrine to a Shinto deity, symbolizing the subjugation and incorporation of formerly rebellious regional powers into the Yamato court's central authority.