During the Vedic period itself the architectural knowledge and capabilities of Hindus had progressed a lot.  The branch of science dealing with architecture was called 'Vaasthu - Vidhya'.  And, the books that enunciate this were called Vaasthu - Sasthra works.  Mythological books like Matsyapurana, Vishnu dharmothra purana and so on, and books on Scripture like 'Hayasirsha Pancharatra Agama', 'Vaiganasa Agama' etc lay down the rules and regulations of temple - structure.  In the mediaeval period some more books came into being in this branch of science.  Manasara, Shilpaprakasha and the like are noteworthy.  In Tamil also there appeared books such as Chinthamani, Sirparathnam etc.  Though there exists some dissimilarities between these, they were having a common viewpoint in general.  Usually the divine sculptor Viswakarma is called the principal author of North Indian books on architecture.   Mayan is usually referred to as the principal author of south Indian works.  From the rules and norms laid down by these books on architecture we can see how much religion had influenced the structural patterns of the city and its buildings.  Till the mediaeval period all those available informations pertaining to the field had been orally passed on from father to son and so on.  Only in the mediaeval period all those available informations about the field were for the first time recorded in the palmyra leaves in the written form of language.  In the year 1920 a person called Stella Kramisch had studied very many of these palmyra leaves.  Let us look at some of the important information's that these leaves impart.  In particular, let us look at the information's on city layout.

Universe and Hindu's Architecture:
In the philosophies of the Upanishads of Hindus, we find descriptions
about 'Brahmam' or Brahma.  He who has no beginning nor end and who is
'Omnipresent' is Brahma.  And, gods like Siva, Vishnu, Brahma and others are
the physical images of this formless Brahma.  And, he who is called 'Vasthu
Purushan' or 'Vasthu Dhevan' is the one who had been created out of this
formless principal image.  And, having him as the focal point, the field of
architecture of the Hindus had progressed.  The above - mentioned books on
architecture describe this image with a physical form, the Vasthu Purusha as
the Vasthu Purusha Mandalam (Vasthu Male zone).  And, in the same way how
the physical form of Vasthu Purusha was created out of the formless brahman,
the architects also while shaping the formless environment into buildings
with concrete forms make it a point to do it in a way that would please and
satisfy the Vasthu Deva mentioned above.  From this it becomes evident that
the Hindus preserved the association between Man and Universe even in
constructing buildings.

CIRCLE, SQUARE AND THE VASTHU PURUSHA ZONE.
Those who view the buildings of Hindus and that of Budhists would
easily comprehend one thing.  Budhists building towers have been built in a
round, circular shape.  But, the buildings of Hindus are of square or
rectangular shape.  Anuradhapuram is one of the important cities of the
Budhists.  How much the round or circular shape had influenced the ancient
city and building style of architecture is brought out by a sinhalese
professor by name Rolan-de-silva who has undertaken an in-depth study of the
said issue.  In the ancient Anuradhapura city which was created with the market
place as the axis, round - shaped stupas (Thadhu Gopangal) around the city
of Anuradhapura in a circular fashion, were built in two different streams, and
these informations are authentically arrived at in his investigations.  The
circular form implies 'motion' or movement.  Birth and Death, Night and
Day - so the passage of time which moves on in a sort of circular motion is
implied in the above - mentioned round shape.  Further, this round shape
would also refer to the nature or character of the world we are in.  That
the Budhists who believe more in the doctrine of materialism chose the round
shape is no surprise at all.

Unlike it the square - shape is a decisive and clear form.  It doesn't
imply motion as like the circular form.  The Hindus viewed this Universe as
a square shaped space created by such others and identified the impact of
time on this space in terms of 'Rasis' (Zodiac).  From this it becomes clear
that as claimed by the Neo-physics the hindus too had understood this Universe as a spatial time frame.  And, the fact that the hindus who identified this
Universe as a square-shaped frame have structured the buildings and cities
too which had been constructed based on these laws as square-shaped (or
rectangular) is not something surprising.

Thus, cities and buildings were structured, keeping in line with this
'Vasthu Purusha Mandala' formed in square shape.  Each and every god was
created as small small squares.  This square-shaped 'Vaashtu Purusha
Mandala' was divided into many more small, tiny squares.  And, these small,
tiny squares were called 'Padas'.  Each small square would be occupied by a
god.  And, in the centre of Vaasthu Purusha Mandala there would be a big
square comprising of many small squares.  This square stood for Brahma.

Manduka Mandala:

1. Brahma's four squares.
2. Belonging to the next important gods 2 squares.
3. Belonging to the rest of the gods. 1 square.

The above cited Vaasthu Purusha Mandala would be divided in such a way
with the squares of the gods comparitively  of less importance surrounding
Brahma.  Vaasthu Purusha Mandala can be formed in 32 different ways in
square – shape.From a square shaped Vaasthu Purusha Mandala
4,9,16,25,36,49,64,81……… and so on, in thirty - two different ways
comprising of 1024 small squares, the Vaasthu Purusha Mandala can be made
.This is enunciated in out ancient Indian books on
architecture.  In such Vaasthu Purusha Mandalas or zones that which is
called 'Manduka Mandala' comprising of 64 small squares and another called
Parama Sayika Mandala comprising of 81 small squares are important :

Parama Sayika Mandala :

As for 'Manduka Mandala' the whole square would be divided by the two
axes that go North-south and East-west.  In the case of 'Parama Sayika
Mandala' the entire squire would be unevenly divided. Thus, each and every
building (be it a temple or a house) and city that are constructed according
to the architectural norms or laws of hindhus stand as symbols highlighting
the hindhus' laws and principles of creation in right earnest, and, they are structured in such a way as to reveal the modes and codes of Hindhus's laws of creation, so to say.  This, in turn, reveals the key role that religion plays in our city and building construction - works. (Though there exists slight differences between the Vaasthu Purusha Mandala spoken of in North Indian books of Architecture and that explained in South Indian Works, in general, there is no great difference or disparity.  In the South Indian temple cities of Madurai,  Srirangam and such others this difference or deviation is clearly perceivable)