《隋书·帝纪·卷三》
此后高祖每逢在仁寿宫避暑时，就令炀帝留守，代行处理国政。
是后高祖每避暑仁寿宫，恆令上监国。
From then on, whenever Gao Zu retreated for the summer, he ordered Emperor Yang to remain, taking his place in handling state affairs.
<s>[INST] Kindly elucidate the central themes in this passage in English: 是后高祖每避暑仁寿宫，恆令上监国。 [/INST] From then on, whenever Gao Zu retreated for the summer, he ordered Emperor Yang to remain, taking his place in handling state affairs.</s>
Kindly elucidate the central themes in this passage in English: 是后高祖每避暑仁寿宫，恆令上监国。
user
From then on, whenever Gao Zu retreated for the summer, he ordered Emperor Yang to remain, taking his place in handling state affairs.
assistant