This study considers the relationship between the approach to urban planning in Portugal up to the eighteenth century, and the effective process of urbanisation, from both a theoretical and practical perspective. Portuguese urban layout does not develop as a set of random shapes but rather arises from structured thinking by “urban makers” who are firmly grounded in the subject of geometry. Being able to measure the universe and codify it in drawings was one of the major scientific accomplishments of the age of Portuguese discoveries in the sixteenth century and the acquisition of such knowledge demanded a unique ability for abstraction which could not have simply emerged out of nothing. Portugal’s investment in the training of skilled professionals is made evident in treatises, manuals, dissertations, and cartography and iconography works. The interpretation of the ideas of Order and Space in urban design evolved through history in parallel with the evolution of philosophical and scientific thought. In fact, urban space is associated the search of the laws of the nature and the intelligibility of the cosmos.