This chapter discusses the morphosyntax of French, Modern Greek, Serbo-Croatian, and Bulgarian complementizers equivalent to English that. From long-distance wh-extractions across complementizers in these languages, it is shown that (i) the morpheme complementizer is composed of features that are hierarchically ordered according to a functional sequence (fseq) (see Baunaz 2015, 2016a; Baunaz and Lander to appear); (ii) the complementizer morpheme lexicalizes structures of different sizes; (iii) the distribution of complementizers is governed by veridicality (see Baunaz 2015, 2016a); (iv) the complementizer morpheme is syntactically active. The basic template for complementizers that I argue for is F4 > F3 > F2 > F1. Evidence in favor of this template comes from crosslinguistic patterns of syncretism and featural Relativized Minimality (Starke 2001; Rizzi 2004; Haegeman 2010, among others). Evidence in favor of different realizations of the complementizer is provided by means of long-distance extractions across declarative embedded clauses.