There has been considerable discussion about the alternation of the overt complementizer that and its nonovert counterpart zero throughout the history of English (Jespersen 1909-1949: III, Bolinger 1972, Warner 1982, Fanego 1990, Rissanen 1991, López-Couso 1994, Finegan and Biber 1995, García-Lorenzo 2001). The English complementizer zero has been traced from the Old English period (OE) (Mitchell 1985), thus attesting that it is historically wrong to consider it as a mere omission of the marker that. Diachronic investigation also shows that both that and zero have been used from OE as ways of linking complement clauses to their matrices. Use of unintroduced clauses becomes more noticeable from late Middle English and reaches a peak of popularity in early Modern English (EMODE), before initiating a decline from the eighteenth century. Points of interest on this topic include the analysis of those contexts which trigger off mandatory, or almost mandatory, selection of either the nonovert complementizer or of the marker that. I also analyze the complex and generally interrelated factors governing the noncompulsory choice between that and zero. The most important of these have proved to be: (1) Style: formal varieties of English being said to show a preference for that. (2) Frequency of the matrix predicate. (3) Presence of elements between predicate and clause. (4) Nature of the lower-clause subject, pronominal subjects having been found to favour zero.
    I will discuss results from John Lyly’s Euphues. The Anatomy of Wyt (1578), a corpus of circa 60,000 words, which has proved to yield statistically reliable results on frequency and distribution. I will also be using data from other corpora, especially López-Couso’s analysis of Dryden (1994) in an attempt to clarify and interpret the distribution of complementizers in EMODE.

References
Aarts, B. and C.F. Meyer eds. 1995. The Verb in Contemporary English. Theory and Description. Cambridge: Cambridge University Press.
Aijmer, K. and B. Altenberg eds. 1991. English Corpus Linguistics. Studies in Honour of Jan Svartvik. London and New York: Longman.
Bolinger, D. 1972. That's that. The Hague: Mouton.
Fanego, T. 1990. "Finite Complement Clauses in Shakespeare's English. Parts I & II." Studia Neophilologica 62: 3-21 and 129-149.
Finegan, E. and D. Biber. 1995. "That and Zero Complementisers in Late Modern English: Exploring ARCHER from 1650-1990." In Aarts, B. and C.F. Meyer (edd): 241-257.
García-Lorenzo, J.C. 2001. Complementation in John Lyly’s English. Unpublished Ph.D. dissertation. University of Santiago de Compostela.
Jespersen, O. 1909-1949. A Modern English Grammar on Historical Principles, I-VII. London: Allen & Unwin.
López-Couso, M.J. 1994. Finite Complementation in the Works of John Dryden. A Corpus-based Study. Unpublished Ph.D. dissertation. University of Santiago de Compostela.
Mitchell, B. 1985. Old English Syntax. 2 vols. Oxford: Oxford University Press.
Rissanen, M. 1991. "On the History of That/Zero as Object Clause Links in English." In Aijmer, K. and B. Altenberg eds.: 272-289.
Warner, A. 1982 Complementation in Middle English and the Methodology of Historical Syntax. London and Canberra: Croom Helm.