The altar in a Greek temple, which stood in the centre of the building and in front of the statue of the presiding deity, was generally of a circular form, and constructed of stone. It was customary to engrave upon it the name or distinguishing symbol of the divinity to whom it was dedicated; and it was held so sacred that if any malefactor fled to it his life was safe from his pursuers, and it was considered one of the greatest acts of sacrilege to force him from this asylum.
The most ancient altars were adorned with horns, which in former times were emblems of power and dignity, as wealth, and consequently importance, consisted among most primitive nations in flocks and herds.
In addition to those erected in places of public worship, altars were frequently raised in groves, on highways, or in the market-places of cities.
The gods of the lower world had no altars whatever, ditches or trenches being dug for the reception of the blood of the sacrifices offered to them.