  We re-examine the long-standing problem of the date of the Cassiopeia A
supernova (SN), in view of recent claims that it might be the 1630 "noon-star"
seen at the birth of King Charles II. We do not support this identification,
based on the expected brightness of a Type-IIb SN (too faint to be seen in
daylight), the extrapolated motion of the ejecta (inconsistent with a date
earlier than 1650), the lack of any scientific follow-up observations, the lack
of any mention of it in Asian archives. The origin of the 1630 noon-star event
(if real) remains a mystery; there was a bright comet in 1630 June but no
evidence to determine whether or not it was visible in daylight. Instead, we
present French reports about a 4th-magnitude star discovered by Cassini in
Cassiopeia in or shortly before 1671, which was not seen before or since. The
brightness is consistent with what we expect for the Cas A SN; the date is
consistent with the extrapolated motion of the ejecta. We argue that this
source could be the long-sought SN.
