Witnesse I take, of _Georgio Vasari_, _Pittore Aretino_: of _Pomponius Gauricus_: and other. To these two Artes, (with other,) is a certaine od Arte, called _Althalmasat_, much beholdyng: more, then the common _Sculptor_, _Entayler_, _Keruer_, _Cutter_, _Grauer_, _Founder_, or _Paynter (&c)_ know their Arte, to be commodious. [An objection.] +‡Architecture‡+, to many may seme not worthy, or not mete, to be reckned among the _Artes Mathematicall_. To whom, I thinke good, to giue some account of my so doyng. Not worthy, (will they say,) bycause it is but for building, of a house, Pallace, Church, Forte, or such like, grosse workes. And you, also, defined the _Artes Mathematicall_, to be such, as dealed with no Materiall or corruptible thing: and also did demonstratiuely procede in their faculty, by Number or Magnitude. First, [The Answer.] you see, that I count, here, _Architecture_, among those _Artes Mathematicall_, which are Deriued from the Principals: and you know, that such, may deale with Naturall thinges, and sensible matter. Of which, “some draw nerer, to the Simple and absolute Mathematicall Speculation, then other do. [☞] And though, the _Architect_ procureth, enformeth, & directeth, the _Mechanicien_, to handworke, & the building actuall, of house, Castell, or Pallace, and is chief Iudge of the same: yet, with him selfe (as chief _Master_ and _Architect_,) remaineth the Demonstratiue reason and cause, of the Mechaniciens worke: in Lyne, plaine, and Solid: by _Geometricall_, _Arithmeticall_, _Opticall_, _Musicall_, _Astronomicall_, _Cosmographicall_” (& to be brief) by all the former Deriued _Artes Mathematicall_, and other Naturall Artes, hable to be confirmed and stablished. If this be so: then, may you thinke, that _Architecture_, hath good and due allowance, in this honest Company of _Artes Mathematicall_ Deriuatiue. I will, herein, craue Iudgement of two most perfect _Architectes_: the one, being _Vitruuius_, the Romaine: who did write ten bookes thereof, to the Emperour _Augustus_ (in whose daies our Heauenly Archemaster, was borne): and the other, _Leo Baptista Albertus_, a Florentine: who also published ten bookes therof. _Architectura_ (sayth _Vitruuius_) _est Scientia pluribus disciplinis & varijs eruditionibus ornata: cuius Iudicio probantur omnia, quæ ab cæteris Artificibus perficiuntur opera._ That is. +Architecture, is a Science garnished with many doctrines & diuerse instructions: by whose Iudgement, all workes, by other workmen finished, are Iudged.+ It followeth. _Ea nascitur ex Fabrica, & Ratiocinatione. &c. Ratiocinatio autem est, quæ, res fabricatas, Solertia ac ratione proportionis, demonstrare at[que] explicare potest. +Architecture, groweth of Framing, and Reasoning. &c. Reasoning, is that, which of thinges framed, with forecast, and proportion: can make demonstration, and manifest declaration.+_ Againe. _Cùm, in omnibus enim rebus, tùm maximè etiam in