There is significant variation in the literature on how demonstratives are characterized semantically, leading to divergent syntactic analyses of demonstratives. A major source of this disagreement regards how distance specifications relate to the demonstrative: whether [+/- speaker] is an integral property of the demonstrative or not. I argue that distance-marking divides the class of demonstratives into strong and weak, along the lines of what Cardinaletti and Starke (1999) propose for pronouns. Strong demonstratives possess a [+/- speaker] feature, while weak demonstratives have a neutral [speaker] feature, corresponding to a distance-neutral interpretation, and the pragmatic notion of immediate accessibility of the referent (Lyons 1999). The diachronic component of this work serves as a lens through which to view the demonstrative's synchronic behavior. I argue that the process of grammaticalization (Meillet 1912) allows us to "see" certain aspects of a demonstrative's meaning (and, I argue, corresponding internal syntactic structure) getting peeled away as the demonstrative evolves. Latin "ille" and spoken Finnish se provide evidence that demonstratives pass through a distance-neutral phase before being analyzed as definite articles, suggesting that strong and weak demonstratives should receive distinct analyses in the synchronic domain. I argue that strong and weak demonstratives can be viewed as synchronic imprints of a diachronic process. In addition to teasing apart different semantic types of demonstratives, this dissertation seeks to identify differences between demonstratives and definite articles. I propose that the demonstrative is specified for (i) [(+/-) speaker], (ii) [+contrastive] (encoding contrast), and (iii) [+identifiability], and that these features are encoded on functional heads in the extended projection of the demonstrative. The complex demonstrative is merged in a dedicated functional projection ([Spec, TrackerAdjP) within the DP. The definite article, in contrast, expresses only [+identifiability], and is merged directly in the DP projection. I argue that the common core of [+identifiability] helps explain the synchronic and diachronic dependency between the demonstrative and the DP projection, and sheds light on our discussion on the phenomenon of apparent "double definiteness." [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://www.proquest.com/en-US/products/dissertations/individuals.shtml.]