The only way to gain insight into ancient architectural planning is by converting the metric dimensions into the architect's foot unit, which must be calculated on the basis of measurements within the building. In the case of the Lefkandi ‘heroon’, a monumental building unique for its time, such an analysis is rewarding. When we try a foot length of 30 cms, the repartition becomes clear. The width (interior measurement 30 ft) consists of two equal naves of 15 ft. This bay determined the interior length of (10 × 15 ft =) 150 ft. This length was divided into a main room of (5 × 15 ft =) 75 ft, and the remaining half was divided into a front hall (30 ft), the north and south rooms (15 ft), and the apse room (30 ft). To these interior dimensions lengthwise were added a porch of 8 ft, a rear wall (2 ft) and a colonnade (6 ft), a total of 166 ft (11 × 15 + 1 ft). To the interior width (30 ft) were added two length walls (2 × 2 ft) and the colonnade (2 × 6 ft): a total of (30 ft + 2 × 2 ft + 2 × 6 ft =) 46 ft. Reduced to these foot measurements the Lefkandi ‘heroon’ appears to us as a simple construction, in which the interaxial or bay of 15 ft seems to be the planning unit for the ground plan.