Sheep are among the first animals that humans domesticated and used as livestock. This occurred around 10,000 years ago in the Middle East. Today, sheep are found in large parts of the world, and over time, more than 200 different sheep breeds have been developed. As the name suggests, the Old Norwegian Spæl Sheep is a Norwegian breed with roots in the Old Norwegian Sheep – the most original type of sheep in Norway. This breed was officially recognized as a distinct breed in 2002 and has since been valued for its unique characteristics and historical significance.

The breed likely dominated in Norway until the 1600s–1700s. In the early 1700s, sheep from Britain were imported, as they were larger, had finer wool, long tails, and higher slaughter weights. As agriculture became more intensive, these imported sheep were preferred over the local short-tailed breeds. This almost led to the disappearance of the original Norwegian sheep breeds. Today (2023), there are around 14,000 individuals of the Old Norwegian Spæl Sheep, meaning it is not classified as an endangered breed. However, despite not being considered threatened, the breed remains vulnerable, making it important to monitor the population to prevent it from reaching an endangered state.

Modern breeding efforts focus on preserving the diversity of color variations in the sheep. These colors include black, gray, blue, brown, light brown, white, and white markings on the head and body. Rare and historical color patterns such as "grelet," "mouflon-colored," and "English gray" are also prioritized for conservation.