Also see definition of "Allegiance" in Word Study
Allegiance
ALLEGIANCE [isbe]
ALLEGIANCE - a-le'-jans (mishmereth, "a charge," from shamar, "to keep," 1 Ch 12:29): the Revised Version, margin gives as literal meaning, "kept the charge of the house of Saul," which revisers consider figurative for "maintaining their loyalty and fidelity," i.e. "allegiance."
Also see definition of "Allegiance" in Word Study