Although the Messier catalog ended at number 103 at the time of Charles Messier's death, objects 104-110 were attributed to him as there is evidence he observed them. Working with a 4 inch telescope mostly from within the city of Paris, the Messier catalog is an outstanding achievement.
M110 is a small, elliptical galaxy that is gravitationally bound to M31, the great Andromeda Galaxy. It is amazing that Messier could even see this small, faint object; it's a tribute to his eyesight and to the excellent sky conditions that must have existed at the end of the 18th century, even in a major city.
This image shows M110 as a faint, elliptical haze close to the center of the image. To the upper left are the huge core and dust lanes of M31.