EXCUBILE, in Antiquity, the watches and guards kept in the daytime by the Roman soldiers. They are distinguished from the vigilia, which were kept in the night. The excubia were placed either at the gates and entrenchments, or in the camp; for the latter there was allowed a whole manipulus to attend before the pratorium, and four soldiers to the tent of every tribune. The excubia at the gates of the camp, and at the entrenchments, were properly called stationes. One company of foot and one troop of horse were assigned to each of the four gates every day. To desert his post, or to abandon his corps of guards, was an unpardonable crime in the Roman soldier.
The triarii, as the most honourable class of soldiers, were excused from the ordinary watches; yet being placed opposite to the equites, they were obliged to have an eye over them.