The Groma was an essential tool in ancient Roman surveying, known for its role in the layout of cities, roads, and agricultural land. This instrument was used by Roman surveyors, or Agrimensores, to establish straight lines and right angles, crucial for the precise division and measurement of land.
The Groma consisted of a vertical staff with a horizontal cross at the top. This cross was fitted with four equal-length arms, each ending in a plumb line. These plumb lines, when suspended, formed a perfect cross and allowed surveyors to:
Evidence suggests that the Groma was in use from at least the 3rd century BC. Its invention is attributed to the Etruscans or the Greeks, but it was the Romans who refined its use for their extensive land division projects:
The precision of the Groma allowed for:
The tool's simplicity and effectiveness made it a staple in Roman surveying practices for centuries. However, its use declined with the advent of more advanced surveying techniques and instruments in the Middle Ages.
Remains of Gromas have been discovered in various Roman sites, providing insight into their construction and usage. These findings are often cited in archaeological reports:
For more information on the Groma and its historical context, consider the following sources: