Henry C. Calhoun is the son of Granville Calhoun, who speaks in the previous poem.
Granville had been the County Judge for many years, and wanted to be elected one more time so that he could "round out a service / Of thirty years." His friends, however, betrayed him, and "a new man" was elected. Granville was "seized" with "a spirit of revenge," with which he infected his four sons.
Henry revenged his father's disappointment by rising to "the highest place in Spoon River." It is not clear from the poem exactly what this position is; the poem only says that Henry sought "wealth and...power" with a "furious energy."
Although the poem does not specify, it seems that Henry's rise to power did not bring happiness with it. He describes revenge as "an envenomed [poisoned] robe," and advises us to avoid it.
In giving his advice, Henry uses allusions to classic Greek mythology. He says that his father sent him along "the path that leads to the grove of the Furies." The Furies were three goddesses who punished mortals for their crimes.
He also refers to the Fates, three goddesses who controlled human destiny. He says that if you see them weaving, and you see the "thread of revenge," you should cut it away, "lest your sons, / And the children of them and their children / Wear the envenomed robe."