Tamar cannot be called one of the children of David, because she was born before her mother's conversion to Judaism. Consequently, her relation to Amnon is not quite of the grave nature it would have been, had they been sister and brother in the strict sense of the terms.
To the immediate household of David belonged four hundred young squires, the sons of women taken captive in battle. They wore their hair in heathen fashion, and, sitting in golden chariots, they formed the vanguard of the army, and terrified the enemy by their appearance.