The badge is the black double-headed eagle surrounded by a blue-enamelled ornamented border, with the inscription Salus et Gloria on a white fillet; the eagle bears a red Greek cross with gold and blue borders.
Contemporary documents prove that the interior was begun in 1508 by Cola Matteuccio da Caprarola, and the exterior completed in1516-1524by Ambrogio da Milano and Francesco di Vito Lombardo; the slender dome was not added till .1606; its plan is a Greek cross.
The plan is a Greek cross with four octagonal towers supported on the barrel vaulting of the four arms of the cross.
In plan (see the article Architecture) St Mark's is a Greek cross of equal arms, covered by a dome in the centre, 42 ft.
It is formed by combining the Greek cross with the Greek letter chi (X) first letter of Christ in Greek.
