Trimarcisia (Ancient Greek:τριμαρκισία,trimarkisia), i. e., "feat of three horsemen",[1] was an ancientCeltic militarycavalrytactic or organisation;[2] it is attested inPausanias'Description of Greece, where he describes the use oftrimarcisia by theGauls duringtheir invasion of Greece in the third century BCE.[3][4][5]
According to Pausanias:
When theGallic horsemen were engaged, the servants remained behind the ranks and proved useful in the following way. Should a horseman or his horse fall, the slave brought him a horse to mount; if the rider was killed, the slave mounted the horse in his master's place; if both rider and horse were killed, there was a mounted man ready. When a rider was wounded, one slave brought back to camp the wounded man, while the other took his vacant place in the ranks.
Pausanias' view was that the Gauls had adopted this method of fighting by copying the PersianAthanatoi elite force with the difference that while the Persians waited until after a battle to replace their casualties, the Gauls "kept reinforcing their full number during the height of the action".[3]
According to Pausanias,marka was the Celtic name for a horse.[3] This corresponds to theroot*mark-os of words for "saddle horse" attested inCeltic andGermanic but not in otherIndo-European languages, a root that is of uncertainetymology.[6]