The name Britni is a variant of the Old English name Bryten, which means "Britain" or "the British Isles." It has its roots in the Proto-Celtic language and is derived from the word *Brittanī, which referred to the Celtic inhabitants of the British Isles. The earliest known use of the name Bryten dates back to the 6th century AD, when it was used to identify the people and territory of Britain.

The name Britni gained popularity during the Middle Ages, particularly in England and parts of Europe where the influence of the English language and culture was strong. During this time, the name was often associated with the concept of British identity and the rise of the English monarchy.

One of the earliest recorded instances of the name Britni can be found in the Domesday Book, a great survey of land ownership in England commissioned by William the Conqueror in 1086. In this document, there are several references to individuals with the name Bryten or similar variants.

Throughout history, there have been several notable figures who bore the name Britni. In the 12th century, Britni was the name of a Welsh princess who married Gruffydd ap Rhys, the Prince of Deheubarth in Wales. Another notable figure was Britni de Ferrers, a 13th-century English noblewoman and heiress to the Ferrers estate.

In the realm of literature, the name Britni appeared in the 14th-century poem "Sir Gawain and the Green Knight," where it was used to refer to a character named Bryten, a knight of King Arthur's Round Table.

During the Renaissance period, the name Britni was adopted by several artists and intellectuals, including Britni Arundel, an English painter and illustrator who lived in the 16th century, and Britni Jonson, a renowned English playwright and poet from the 17th century.

In more recent times, the name Britni has been associated with Britni Spears, an American singer and performer who rose to fame in the late 1990s and early 2000s, and Britni Murphy, an American actress who appeared in films such as "8 Mile" and "Just Married" before her untimely death in 2009.