What does the phrase "Queen of empires and the nurse of arms" signify?

This phrase is from the poem "The Future Glory" by John Trumbull. He was a renowned American poet who lived from 1750 to 1831.

This phrase is the last line in one of the stanzas in his poems. The poet starts the stanza with praises for the proverbial Queen. He describes her splendour and her radiance. This phrase for the Queen suggests that the Queen is the ruler of all the empires but when she sees her own men who were fighting for her glory and rule injured, she becomes a nurse to them and brings them back to health.