The name was changed to Wireshark in June, 2006, because creator
and lead developer
Gerald Combs could not keep using the
Ethereal
trademark (which was then owned by his old employer,
Network Integration Services) when he changed jobs. He still
held copyright on most of the source code (and the rest was
redistributable under the
GNU General Public License), so he took the
Subversion repository for Ethereal and used it as the basis
for the Subversion repository of Wireshark.
It appears that Ethereal development has ceased, and an Ethereal security advisory recommended switching to Wireshark.