The central theme of “Tamerlane” is the unbalanced dynamic between pure love and ruthless ambition. In his monologue to the priest, the title character presents these as two irreconcilable goals; he could not have both values in his life at the same time.

Initially, the speaker believed his lover shared his hunger for power:

The moment's converse; in her eyes

I read, perhaps too carelessly—

A mingled feeling with my own—

The flush on her bright cheek, to me

Seem’d to become a queenly throne (Lines 148-52).

In retrospect, however, the speaker recognizes his own projection onto the lover—in other words, he saw his ambition reflected back at him. In reality, the lover represented a more pure and innocent source of fulfilment than the emptiness of endless war. Once the speaker understood the divide between them, he turned away toward new endeavors: “Why did I leave it, and, adrift, / Trust to the fire within, for light?” (Lines 94-95). The idea of both love and power as sources of light is prevalent throughout the poem; they are two sides of the same dynamic, which has led the speaker to ultimately see them as inversions of each other.

The poem is clear in its thematic intent; Tamerlane looks back on the choice he made as the wrong one.