The Starfleet ship whose command William Riker was offered, and declined, in 2365.
The USS Aries was a Starfleet starship assigned to a long mission of exploration in 2365. When its captaincy fell open, Starfleet offered command of the Aries to William Riker, then first officer of the Enterprise-D.
Riker's estranged father, Kyle Riker, came aboard the Enterprise to brief him on the posting, reopening old tensions that the two finally confronted in a bout of anbo-jitsu. Although the assignment would have been his first command, Riker ultimately turned down the Aries and stayed aboard the Enterprise, one of several such offers he declined over the years.