What are the differences in ideological themes between the war poems in The Book of Songs and those in Han Dynasty and frontier poems in the prosperous Tang Dynasty?

The Book of Songs is the earliest collection of poems in China, which contains a large number of war poems, such as Guan Ju, Jia Jian and Mi Li. In these poems, war is praised as an important cause of the country, praising the courage of generals, the loyalty of soldiers and the sacrifice of the people.

The war poems of the Han Dynasty put more emphasis on individual heroism, such as Into the Wine and Chen. In these poems, war is a dangerous adventure, which requires heroes to go forward bravely and forget their lives.

Frontier poems in the prosperous Tang Dynasty paid more attention to frontier life and frontier wars, such as Wang Zhihuan's Lodge of Herons and Du Fu's Ascending the Mountain. In these poems, war is described as the normal state of frontier life, and the life of frontier people is troubled by war.

It can be seen that the war poems in these three periods are different in ideological theme. The Book of Songs emphasizes national interests, the war poems in Han Dynasty emphasize heroism, and the frontier poems in prosperous Tang Dynasty emphasize the relationship between life and war. This reflects the changes of society and the evolution of ideas in different times.