GROMATICI (from groma or gruma, a surveyor's pole), or Agrimensores, the name for land-surveyors amongst the Romans. The art of surveying was probably at first in the hands of the augurs, by whom it was exercised in all cases where the demarcation of a templum (any consecrated space) was necessary. Thus, the boundaries of Rome itself, of colonies and camps, were all marked out in accordance with the rules of augural procedure. The first professional surveyor mentioned is L. Decidius Saxa, who was employed by Antony in the measurement of camps (Cicero, Philippics, xi. 12, xiv. 10). During the empire their number and reputation increased. The distribution of land amongst the veterans, the increase in the number of military colonies, the settlement of Italian peasants in the provinces, the general survey of the empire under Augustus, the separation of private and state domains, led to the establishment of a recognized professional corporation of surveyors. During later times they were in receipt of large salaries, and in some cases were even honoured with the title clarissimus. Their duties were not merely geometrical or mathematical, but required legal knowledge for consultations or the settlement of disputes. This led to the institution of special schools for the training of surveyors and a special literature, which lasted from the 1st to the 6th century A.D. The earliest of the gromatic writers was Frontinus (<?..), whose De agrorum qualitale, dealing with the legal aspect of the art, was the subject of a commentary by Aggenus Urbicus, a Christian schoolmaster. Under Trajan a certain Balbus, who had accompanied the emperor on his Dacian campaign, wrote a still extant manual of geometry for land surveyors (Exposilio et ratio omnium j or mar urn or mensurarum, probably after a Greek original by Hero), dedicated to a certain Celsus who had invented an improvement in a gromatic instrument (perhaps the dioptra, resembling the modern theodolite) ; for the treatises of Hyginus see that name. Somewhat later than Trajan was Siculus Flaccus (De condicionibus agrorum, extant), while the most curious treatise on the subject, written in barbarous Latin and entitled Casat litlerarum (long a school textbook) is the work of a certain Innocentius (4th-sth century). It is doubtful whether Boetius is the author of the treatises attributed to him. The Gromatici veteres also contains extracts from official registers (probably belonging to the 5th century) of colonial and other land surveys, lists and descriptions of boundary stones, and extracts from the Theodosian Codex. According to Mommsen, the collection had its origin during the sth century in the office of a vicarius ( diocesan governor) of Rome, who had a number of surveyors under him. The surveyors were known by various names: decempedator (with reference to the instrument used) ; finilor, metator or mensor castrorum in republican times; togati Augustorum as imperial civil officials; professor, auctor as professional instructors.
The best edition of the Gromatici is by C. Lachmann and others (1848) with supplementary volume, Die Schriftert der romischen Felamesser (1852); see also B. G. Niebuhr, Roman History, ii., appendix (Eng. trans.), who first revived interest in the subject; M. Cantor, Die romischen Agrimensoren (Leipzig, 1875); P. de Tissot, La Condition des Agrimensores dans I'ancienne Rome (1879); G. Rossi, Groma e squadro (Turin, 1877); articles by F. Huftsch in Ersch and Gruber's Allgem. Encyklopadie, and by G. Humbert in Daremberg and Saglio's Dictionnaire des antiquites; Teuffel-Schwabe, Hist, of Roman Literature, 58.
Note - this article incorporates content from Encyclopaedia Britannica, Eleventh Edition, (1910-1911)