The name Dennis has its origins in the ancient Greek language. It is derived from the Greek name Dionysios, which was a theophoric name meaning "follower of Dionysus," the Greek god of wine, vegetation, pleasure, festivity, madness and wild frenzy. The name Dionysios was later Latinized to Dionysius.

The name Dennis emerged as a French diminutive form of Dionysius, taking the form "Denis" in French. It is believed that the French form Denis was introduced to England after the Norman Conquest in 1066, where it eventually evolved into the English spelling Dennis.

One of the earliest recorded examples of the name Dennis is Saint Dennis, also known as Saint Dionysius, who is said to have been the first bishop of Paris in the 3rd century AD. According to tradition, he was martyred and beheaded for his faith around 258 AD, becoming one of the most revered martyrs of the Catholic Church.

Another notable figure in history with the name Dennis is Dennis the Carthusian (1384-1471), a influential Catholic theologian, philosopher, and spiritual writer from the Low Countries. He is best known for his works on mystical theology and his commentaries on various books of the Bible.

In the realm of literature, the name Dennis is associated with the English poet and satirist John Dennis (1657-1734), who was a prominent critic and playwright during the Restoration period in England. He is particularly remembered for his critiques of the works of William Shakespeare and John Dryden.

The name Dennis also has a connection to the American Revolution through Dennis Smythe (1740-1818), an American silversmith and patriot who participated in the Boston Tea Party in 1773. He is credited with being one of the leaders of the "mob" that boarded the ships and dumped the tea into Boston Harbor.

In the realm of science, Dennis Gabor (1900-1979) was a Hungarian-British electrical engineer and physicist who pioneered the theory of holography, for which he received the Nobel Prize in Physics in 1971.

These are just a few examples of notable figures throughout history who bore the name Dennis, illustrating its rich heritage and diverse cultural connections.