A split infinitive is a grammatical construction in which an adverb or adverbial phrase separates the "to" and "infinitive" constituents of what was traditionally called the full infinitive, but is more commonly known in modern linguistics as the to-infinitive (e.g. to go). In the history of English language aesthetics, the split infinitive was often deprecated, despite its prevalence in colloquial speech. The opening sequence of the Star Trek television series contains a well-known example, "to boldly go where no man has gone before", wherein the adverb boldly was said to split the full infinitive, to go. Multiple words may split a to-infinitive, such as: "The population is expected to more than double in the next ten years." In the 19th century, some linguistic prescriptivists sought to introduce a rule proscribing the split infinitive, and the resulting conflict had considerable cultural importance. The construction still renders disagreement, but modern English usage guides have largely dropped the objection to it. The split infinitive terminology is not widely used in modern linguistics. Some linguists question whether a to-infinitive phrase can meaningfully be called a "full infinitive" and, consequently, whether an infinitive can be "split" at all. History of the construction Old and Middle English In Old English, infinitives were single words ending in -n or -an (comparable to modern Dutch and German -n, -en). Gerunds were formed using to followed by a verbal noun in the dative case, which ended in -anne or -enne (e.g., tō cumenne = "coming, to come"). In Middle English, the bare infinitive and the gerund coalesced into the same form ending in -(e)n (e.g., comen "come"; to comen "to come"). The "to" infinitive was not split in Old or Early Middle English. The first known example of a split infinitive in English, in which a pronoun rather than an adverb splits the infinitive, is in Layamon's Brut (early 13th century): and he cleopede him to; alle his wise cnihtes. for to him reade; And he called to him all his wise knights / to him advise. This may be a poetic inversion for the sake of meter, and therefore says little about whether Layamon would have felt the construction to be syntactically natural. However, no such reservation applies to the following prose example from John Wycliffe (14th century), who often split infinitives: For this was gret unkyndenesse, to this manere treten there brother. For this was great unkindness,