The "vara castellana" is a historical unit of length that was used in Spain. It was commonly used for land measurement and other purposes in various regions of Spain, especially in the Castile region, which is why it is called the "castellana" vara. The exact length of the vara castellana could vary by region and historical period.
In general, the vara castellana was approximately 835.9 millimeters or about 32.91 inches in length. However, variations existed, and in different parts of Spain and at different times in history, the length of the vara castellana could differ slightly.
Like many historical units of measurement, the vara castellana has largely been replaced by more standardized and modern systems of measurement, such as the metric system. In contemporary Spain, the metric system is the standard for length measurement.
A perch is a unit of length that was historically used in some English-speaking countries, primarily in the United Kingdom. It is equivalent to 5.5 yards or 16.5 feet (about 5.0292 meters). The term "perch" is relatively old and is not commonly used in modern measurements.
Perches were often used in land measurement, particularly in agriculture and real estate. They were also sometimes used in surveying. However, the use of the perch as a standard unit of measurement has largely been replaced by more modern and standardized systems such as the metric system or the imperial system based on feet and yards. As a result, the perch is considered an archaic or historical unit of measurement today.