The modular designs of two significant funerary gardens of the Mughal period, the Humayun's tomb and Taj Mahal complexes, have been analyzed to first highlight the original finding that the designs can be understood by analyzing the dimensions in terms of units mentioned in the Arthasastra, in particular the dhanus (D) measuring 108 angulams (As) and vitasti (V) measuring 12 As, with each A taken as 1.763 cm. This confirms the utilization of traditional building principles of the sub-continent in the construction of these two Mughal masterpieces. Detailed analysis of these structures has also revealed that the builders have consistently avoided building over important intersection points of imaginary horizontal, vertical and diagonal arteries of the grid design, suggesting that Mughal buildings were constructed based on traditional vastu principles of the sub-continent.

It will be highly interesting to understand technical aspects of Islamic architecture in India, with particular emphasis on the mathematical system in the design and planning of Islamic structures. The geometry of the multiple axes as well as the geometry of ratios that were used in the design is of interest. Basic to all these is the understanding of the units of measure to which Islamic structures of the sub-continent were designed and finally constructed. The Mughal period, extending for about 200 years from 1526 AD, is a significant period of the Indian sub-continent. Attention would be focused on Mughal architecture in this paper, because presumably the elements of earlier Islamic architecture of India were well reflected in significant Mughal structures.

The architectural structures from the Mughal period are known for their excellent composition and construction (Asher, 1992). It is understood here that architecture was intimately related to civil engineering in the past. Apart from the most notable example of the Taj Mahal at Agra (Koch, 2006), there are several well-engineered architectural structures meriting careful attention for their artistic and engineering genius. Most Mughal architectural designs of palace and tomb complexes follow certain patterns (Asher, 1992; and Koch, 2006). The plans and designs of several Mughal structures are known (Nath, 1982-2005). However, very few of them have been analyzed for their engineering merit. This situation is also true for most other wonderful engineering structures spread over the vast space and long timeline of the Indian sub-continent. Discussions have primarily focused on artistic and aesthetic merit of structures, rather than highlighting the stupendous engineering skills that went into the creation of these structures. The analysis of these important structures of the sub-continent is important because architecture is an important part of history and culture of a land.

In this paper, the modular architectural design of two important Mughal structures will be analyzed to understand the origin of modular design of Mughal structures, in general. These two structures are the Humayun's tomb complex in New Delhi (Misra and Misra, 2003) and the Taj Mahal complex in Agra (Koch, 2006). These two complexes are wonderful examples of the classical form of well-planned riverfront funerary gardens of the Mughal period. There is one basic inherent difference in the overall design of these complexes, especially the relative placing of the tomb with respect to the garden. While the tomb structure is centrally located in the garden of Humayun's tomb complex, the Taj Mahal mausoleum is placed on a riverfront terrace that is located to the north of the garden. These two complexes have been selected because these are the best good examples to understand the modular design principles of the Mughal period.

History and Culture Journal, Mughal Architecture, Islamic Architecture, Mathematical Systems, Mughal Modular Designs, Taj Mahal Complexes, Mughal Monuments, Traditional Building Principles, Civil Engineering, Measurement Units, Islamic Tradition.