The eruption of a large quiescent filament on 2003 June 11 was preceded by the birth of a nearby active region - a common scenario. In this case, however, the filament lay near a pre-existing active region and the new active region did not destabilize the filament by direct magnetic connection. Instead it appears to have done so indirectly via magnetic coupling with the established region. Restructuring between the perturbed fields of the old region and the filament then weakened the arcade overlying the midpoint of filament, where the eruption originated. The inferred rate (11°day-1) at which the magnetic disturbance propagates from the mature region to destabilize the filament is larger than the mean speed (5-6°day-1) but still within the scatter obtained for Bruzek's empirical relationship between the distance from a newly formed active region to a quiescent filament and the time from active region appearance to filament disappearance. The higher propagation speed in the 2003 June 11 case may be due to the "broadside" (versus ''end-on") angle of attack of the (effective) new flux to the coronal magnetic fields overlying a central section of the axis of the filament. © 2011. The American Astronomical Society. All rights reserved.