The given name Kiefer has its origins in the German language, where it is derived from the word "Kiefer," meaning "pine tree" or "pine cone." This name has been in use since the Middle Ages, with some of the earliest recorded instances dating back to the 13th century in various regions of what is now modern-day Germany.

One of the earliest known bearers of the name Kiefer was a German knight named Kiefer von Gundelfingen, who lived in the late 13th century and fought in the Crusades. Records also show a Kiefer von Dortmund, a merchant and landowner from the city of Dortmund in the 14th century.

In the realm of religion, there are no significant historical figures or mentions of the name Kiefer in ancient texts or scriptures. However, the name's connection to nature and the pine tree may have held symbolic significance in pagan beliefs and folklore of the Germanic regions.

As the use of surnames became more widespread in Europe, Kiefer was adopted as a surname by various families, particularly in areas where pine trees were abundant or where forestry and timber industries thrived. Some notable historical figures with the first name Kiefer include:

1. Kiefer Sutherland (born 1966), a British-Canadian actor known for his roles in films like "Stand by Me" and the TV series "24."

2. Kiefer Douse (born 1986), a Jamaican sprinter who competed in the 2008 and 2012 Olympic Games.

3. Kiefer Ravena (born 1994), a Filipino professional basketball player who has represented the Philippines in international competitions.

4. Kiefer Nübel (born 1996), a German professional soccer player who plays as a goalkeeper for Bayern Munich.

5. Kiefer Crosbie (born 1995), an Australian actor known for his role in the TV series "The Kettering Incident."

While the name Kiefer has seen widespread use throughout history, particularly in German-speaking regions, its popularity has also extended to other cultures and countries over time, with varying spellings and adaptations.