κρούω, κόπτω (τὴν θύραν)
(Phryn. Ecl. 148, Antiatt. κ 15)

D. General commentary

An entry in Phrynichus’ Eclogue (A.1) advises against the use of the phrase κρούω τὴν θύραν (‘to knock at the door’) and recommends κόπτω τὴν θύραν as a preferable alternative. The Antiatticist (A.2) informs us that some scholars placed restrictions on the use of κρούω and that the expression κρούω τὴν θύραν was characteristic of common speech (ἐν τῇ συνηθείᾳ). Since the verb κρούω is in itself already classical and otherwise perfectly admissible in good prose, its use is restricted only in the sense ‘to knock’, for which the aspiring Atticising writer is to prefer κόπτω.

The phrase κόπτω τὴν θύραν, recommended by Phrynichus, appears to have been the standard expression for ‘to knock at the door’ in Attic and is supported by multiple occurrences in Aristophanes’ plays (besides C.1, see Ach. 403, Ra. 460, Pl. 1097, 1101), in Attic oratory (Andocides: 1x, Lysias: 1x, plus an occurrence in a spurious Demosthenic oration), and in Menander (+10x). Such an abundance of comic attestations is unsurprising, since scenes at doors – including door-knocking scenes – are very frequent in comedyComedy: on Aristophanes’ plays see Brown (2008, 349–73); on the comparatively rarer presence of such scenes in tragedy, see Brown (2000, 1–16); on the scenic function of the door more generally, see Caciagli, De Sanctis, Giovannelli, Regali (2016). In antiquity, the frequency of κόπτω ‘to knock’ in comedy attracted the attention of commentators and lexicographers, including Atticist scholars, for various reasons. For instance, the distinction between κόπτω – denoting knocking from outside – and ψοφέω – denoting, conversely, ‘to knock from inside’ (i.e. to signal that one is about to come out) – is recorded by Moeris (κ 13Moer. κ 13) and exploited by Lucian (Sol. 9.27); see also schol. Ar. Nu. 132b, from which the entry on κόπτω in the Suda (κ 2062) derives. Note also the compound θυροκόπος (first occurring in Aesch. Ag. 1195), recorded among the noteworthy terms collected in Phrynichus’ Praeparatio sophistica (75.1–2Phryn. PS 75.1–2).

As for the verb κρούω (from PIE *krous-), it covers a wide range of meanings sharing the underlying notion of ‘hitting’: besides ‘to hit (the door)’ > ‘to knock’, in the phrase at issue, compare also ‘to hit (the cord)’ > ‘to play’ (LSJ s.v. 5; on κρούω and its derivatives in the vocabulary of music and instruments, see Rocconi 2003, 32–51), and ‘to hit (a vessel, to test it)’ > ‘to examine’ (LSJ s.v. 4), but also ‘to hit (the scale)’ > ‘to swindle’. Like κόπτω, κρούω attracted the lexicographers’ attention for various reasons: for instance, Harp. π 28 (on παρακρούω) discusses the meaning ‘to swindle’. Whereas there is no reason to believe that the classical pedigree of the verb itself was ever questioned (see, in A.2, the claim concerning the legitimacy of the standard meaning ‘to hit’, illustrated by C.6), its use in the sense ‘to knock’ met with criticism from stricter Atticists, who rejected it. In fact, there is clear evidence that this sense is already classical: the phrase κρούω τὴν θύραν, discouraged by Phrynichus, occurs twice in Aristophanes’ Assemblywomen (C.2, C.3), once in Xenophon (C.4), and three times in Plato (besides C.5 and Pr. 314d.2, cf. Smp. 212c.7). Phrynichus himself, although he presents this use as ‘forced’ (παραβεβίασται) to some extent, was likely aware of such classical evidence: although he does not cite any passage, he appears to have in mind at least one classical occurrence (ἴσως … που) and, despite clearly preferring κόπτω, hesitates to proscribe the phrase with κρούω altogether.

In light of the number of occurrences in authors generally regarded as ‘the good ones’, one might well be puzzled by Phrynichus’ rejection of the phrase (though, compared with his usual confrontational stance, it is a mild one). If the occurrence in Xenophon can be set aside, given his somewhat uncertain authority within the Atticist canon, Plato and Aristophanes enjoyed a more secure status; however, there may have been reasons to hesitate before treating these specific occurrences as models. Indeed, the use of κρούω ‘to knock’ in Plato’s Protagoras (e.g. C.5) did not escape the critics’ attention, and the Platonic lexicon by Pseudo-Didymus (B.1) informs us that its presence in the dialogue was rejected by some as non-Attic and corrupt (παρεφθαρμένον). It is thus possible that Phrynichus, although being aware of this usage in Plato, regarded it as unreliable. Another possibility is that this usage in the Protagoras was considered marked and functional for Hippocrates’ characterisation; however, in the dialogue the act of knocking vehemently at the door carries no negative connotation and rather emphasises Hippocrates’ eagerness to learn (cf. Caciagli, De Sanctis, Giovannelli, Regali 2016, 37). In the case of Aristophanes, the ‘constraint’ evoked by Phrynichus – since a reference to metrical constraint, as in Ecl. 129Phryn. Ecl. 129, where a disapproved usage in Aristophanes is said to be ‘forced by the metre’ (βιασθεὶς ὑπὸ τοῦ μέτρου, see entry ἥρως, ἥρωες), does not seem likely here – may instead lie in the verb’s sarcastic overtone and its mimetic use of vulgar language. In Aristophanes, the act of knocking at the door is often laced with sarcasm, for instance when the vehemence of the knocking is described as brutal and animal-like or, conversely, when its excessive mildness is parodised (see Caciagli, De Sanctis, Giovannelli, Regali 2016, 13–21). To be sure, the choice of the verb denoting the knocking plays a role in such a characterisation: see, for instance, the use of λακτίζω ‘to kick’, properly said of animals, to describe Strepsiades’ vehement knocking in Nu. 136. In light of this, it is remarkable that, whereas in Aristophanes κόπτω neutrally means ‘to knock at the door’, a trivial and obscene meaning underlies both occurrences of κρoύω ‘to knock’ in the Assemblywomen. Thus, in C.2, the act of knocking metaphorically expresses the urge to defecate, while in C.3 it alludes to sexual intercourse. It may therefore be inferred that this meaning of κρούω already belonged to colloquial language in Aristophanes’ time and that its use was associated with trivial banter, and thus seen as unsuitable for elevated discourse.

Phrynichus’ dislike of κρούω ‘to knock’ may also be explained by the verb’s widespread presence in Biblical Greek, including the well-known maxim ‘knock (κρούετε), and it will be opened to you’ (C.7). The phrase κρούω τὴν θύραν itself occurs in passages of both the Old (cf. Id. 19.22, Ca. 5.2) and the New Testament (beside C.8, cf. At. 12.13; Ap. 3.20), which form the basis of numerous commentaries and inspire rich imagery in Christian writers (see E.). On the one hand, this confirms the colloquial nature of this usage, and, on the other, it must have reinforced Phrynichus’ suspicion of it: in his view, the phrase κρούω τὴν θύραν might have been so closely associated with everyday language and low-level prose that its occasional occurrence in canonical texts (see above) could only be regarded as an exception not to be imitated.

As for the attitude of the Antiatticist (A.2), it is reasonably safe to conclude that it was, as expected, more permissive, and that the lexicographer approved of this usage. Indeed, although the entry assigns the meaning ‘to knock’ (and the obscene figurative extension ‘to bang’) to common speech (συνήθεια) without further comment (nor any classical citation), the gloss may reasonably be read in light of the lexicographer’s tendency to defend usages belonging to the συνήθεια against the more rigorous Atticist camp, often supporting them with a locus classicus (on which see Valente 2015, 49–50; on συνήθεια as a metalinguistic category in Atticist and Byzantine lexica, see AGP vol. 3, forthcoming). As for the relationship between A.1 and A.2, there is no compelling reason to suppose that one responds to the other: A.1 belongs to the first book of the Eclogue, for which a direct use of the Antiatticist by Phrynichus is unlikely, nor the reverse scenario appears any more probable. Rather, the two entries may represent opposing – though not necessarily interconnected – views within the Atticist debate on the same issue (on the relationship between Phrynichus’ Eclogue and the Antiatticist, see Valente 2015, 52–4).

E. Byzantine and Modern Greek commentary

The verb κρούω is attested continuously throughout the history of Greek down to the present time. In Medieval Greek it is common overall and covers a wide semantic range (recorded in LME s.v.); it also occurs in the form κρoύγω, resulting from the transfer to the class of consonant stems through the addition of /ɣ/ (see CGMEMG vol. 3, 1291). Given its biblical background, κρούω in the sense ‘to knock’ occurs with particular frequency – though not exclusively – in Christian texts, homilies, and commentaries throughout the late antique and the medieval period, also owing to the popularity of the image of door-knocking as a metaphor for addressing God (see C.7, C.8) as, for instance, in John Mauropous, Canon 4.9.271–3: ἄνοιξον κἀμοὶ | τὴν θύραν σου κρούοντι | θύραν ἐλέους, Χριστέ (‘Open up to me, [the one] who is knocking at your door, the door of mercy, O Christ’). Another metaphor widely attested in Byzantine texts – including those of the most learned authors – is that of door-knocking in the sense ‘to choose, to devote oneself [to something]’, as, for instance, in Michael Psellus Epistulae 13b.8–9: τῆς μὲν χαμόθεν ἐρχομένης ἄκρῳ δακτύλῳ ἠψάμην αὐτὸς ὁ μηδὲ θύραν κρούσας μαθήσεως (‘I touched with my fingertips that [philosophy] which comes from the ground, when I had not yet knocked at the door of learning’).

Since Byzantine scholars appear to have been aware of the Atticistic preference for κόπτω – see schol. rec. Ar. Ra. 460e, where it is marked with the label Ἀττικῶς (‘[said] in the Attic manner’), and schol. (Tz.) Ar. Ra. 460e – the phrase κόπτω τὴν θύραν also occurs in Byzantine texts, and its use seems to be preferred in more classicising texts. It occurs, perhaps not by chance, in the redaction of the Life of Maximus by Macarius Macres (802), which, among the four extant versions of the Life of Maximus the Hutburner, is the most refined and classicising (see Hinterberger 2025).

κρούω remains standard in Modern Greek, where the phrase κρούω την θύραν is still possible for ‘to knock at the door’, alongside the more common χτυπώ την πόρταν (πόρτα being a loanword from Latin porta ‘gate’, see Dickey 2023, 362). As for κόπτω, it has developed into Modern Greek κόβω via the medieval form κόβγω, owing to the stem’s metaplasm to -βγω (with β as a morphological innovation and an epenthetic γ; see CGMEMG vol. 3, 1275–7). Alongside its basic meaning ‘to cut’, κόβω covers a fairly wide semantic range (see LKN s.v.), but ‘to knock’ is not among its meanings.

F. Commentary on individual texts and occurrences

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