The name Alen has its origins in the Slavic languages, particularly in the Serbo-Croatian linguistic branch. It is a masculine given name derived from the Latin name Alanus, which itself is thought to have originated from the Breton word "alan" meaning "little rock" or "rock."

One of the earliest recorded instances of the name Alen can be found in the 13th century, in the written works of Serbian writer and scholar Stefan Prvovencani. He mentions an individual named Alen who was a member of the Serbian nobility during that time period. This suggests that the name was already in use in the region by the early medieval era.

In the 14th century, the name appears in historical records related to the Republic of Ragusa (modern-day Dubrovnik, Croatia), where an Alen Gundulić is mentioned as a prominent merchant and ship owner. This indicates that the name had spread to coastal areas and was being used by influential families.

During the Renaissance period, the name Alen gained further popularity and recognition. One notable bearer of the name was Alen Crnojević (1499-1528), a Montenegrin lord and military commander who fought against the Ottoman Empire. His exploits and leadership during the Battle of Mohács in 1526 were widely celebrated and immortalized in literature and folklore.

In the 19th century, Alen Ožegović (1820-1888) was a Croatian writer, poet, and journalist who played a significant role in the Croatian National Revival movement. His literary works and contributions to the development of the Croatian language and national identity helped to further popularize the name Alen.

Another prominent figure with the name Alen was Alen Turing (1912-1954), the British mathematician, computer scientist, and codebreaker who made groundbreaking contributions to the fields of computer science and artificial intelligence. His work on the concept of the "Turing machine" and his code-breaking efforts during World War II have cemented his legacy as one of the most influential minds of the 20th century.

While these are just a few examples, the name Alen has been borne by numerous individuals throughout history, reflecting its enduring presence in various cultures and regions.