The name Marny is a diminutive form of the name Mary, which has its origins in the Hebrew name Miryam. Miryam is thought to be derived from the ancient Egyptian words "mr" meaning "beloved" and "ym" referring to the sea. The name was popularized by early Christians as the name of the mother of Jesus Christ in the New Testament.

In the Middle Ages, various spellings and diminutives of Mary emerged across Europe, including Marny. This particular form was most common in parts of France and England during the medieval period. One of the earliest recorded instances of the name Marny dates back to the 13th century in a parish record from the village of Marny-sur-Montrond in central France.

One of the most notable historical figures with the name Marny was Marny de Merle, a 14th-century French noblewoman who served as a lady-in-waiting to Queen Isabeau of Bavaria. She played a crucial role in the political intrigues surrounding the Hundred Years' War between France and England.

Another prominent individual with the name Marny was Marny Parkin (1516-1588), an English apothecary and herbalist who authored several influential works on the medicinal properties of plants. Her book, "The Herbal of Marny Parkin," published in 1576, was widely circulated and became a reference text for generations of healers.

In the 17th century, Marny Delaval (1628-1691) was a renowned English architect and builder who designed several notable buildings, including the Delaval House in Northumberland and the Church of St. Mary the Virgin in Newcastle upon Tyne.

Marny Leclerc (1785-1848) was a French mathematician and professor who made significant contributions to the field of geometry. She was one of the first women to be appointed as a professor at the prestigious École Polytechnique in Paris.

In more recent history, Marny Talbot (1923-2015) was a British actress and singer who appeared in numerous film and television productions throughout her career, including roles in the popular series "Doctor Who" and "Coronation Street."