The name Robby is a diminutive form of the name Robert, which is derived from the Germanic name Hrodebert. This name is composed of the elements "hrod" meaning "fame" and "berht" meaning "bright." The name Robert was introduced to Britain by the Normans after their conquest in 1066.

One of the earliest recorded uses of the name Robert can be found in the Domesday Book of 1086, which was a survey of landowners in England commissioned by William the Conqueror. The name gained popularity in medieval Europe, particularly in France and England, and was borne by several prominent figures in history.

One of the most famous historical figures with the name Robert was Robert the Bruce, the King of Scots who led the Scots to victory over the English in the Wars of Scottish Independence in the early 14th century. He was born in 1274 and died in 1329.

Another notable Robert was Robert Guiscard, a Norman adventurer who became the Duke of Apulia and Calabria in southern Italy in the 11th century. He played a significant role in the Norman conquest of southern Italy and Sicily.

In literature, the name Robert is associated with the character of Robin Hood, the legendary outlaw hero of medieval English folklore. While the name Robin is a diminutive of Robert, it is unclear whether the character was based on a real person named Robert.

Robert Hooke was an English natural philosopher, architect, and polymath who lived in the 17th century (1635-1703). He made significant contributions to various fields, including physics, astronomy, and architecture.

Robert Louis Stevenson was a Scottish novelist, poet, and travel writer known for his works such as "Treasure Island," "Kidnapped," and "The Strange Case of Dr. Jekyll and Mr. Hyde." He lived from 1850 to 1894.

The diminutive form Robby emerged as a popular nickname for Robert, particularly in the 20th century. It has been used as a standalone name, although it is less common than the full form Robert.