  In principle, the light from historical supernovae could still be visible as
scattered-light echoes even centuries later. However, while echoes have been
discovered around some nearby extragalactic supernovae well after the
explosion, targeted searches have not recovered any echoes in the regions of
historical Galactic supernovae. The discovery of echoes can allow us to
pinpoint the supernova event both in position and age and, most importantly,
allow us to acquire spectra of the echo light to type the supernova centuries
after the direct light from the explosion first reached the Earth. Here we
report on the discovery of three faint new variable surface brightness
complexes with high apparent proper motion pointing back to well-defined
positions in the Large Magellanic Cloud (LMC). These positions correspond to
three of the six smallest (and likely youngest) previously catalogued supernova
remnants, and are believed to be due to thermonuclear (Type Ia) supernovae.
Using the distance and proper motions of these echo arcs, we estimate ages of
610 and 410 yr for the echoes #2 and #3.
