It has been a subject of controversy whether Greek and Roman horses were shod. There is no mention of horse-shoes in Greek literature, and it seems improbable that they were used by the Greeks. Xenophon advises the use of a specially constructed stone floor for hardening the horse's hoofs,[59] but in spite of such precautions, it is not surprising to hear that the Athenian cavalry horses sometimes went lame as a result of continuous work on hard ground.[60] Horse-shoes are occasionally (though rarely) spoken of in Roman literature. Their use seems to have been quite exceptional as when Nero, for instance, had his mules shod with silver.[61] In the lower part of Case 51 will be seen a series of iron shoes of the Roman period (No. =510=; fig. 208), for the most part found in the south of France. It is impossible to believe that these were ever used as ordinary horse-shoes. The most plausible theory is that they were "hobbles," put on the feet of horses and other quadrupeds to prevent them straying. The upper part of this same Case contains sets of spurs (No. =511=), most of them probably Roman. The arrangement for attaching the spurs to the heel varies. Two have loops formed by the head and neck of swans, three have discs or knobs, while another has holes for laces. [Illustration: FIG. 208.--IRON HOBBLE (NO. 510). 1:4.] (=502=) _Cat. of Bronzes_, 2695; (=503=) _ibid._, 2696 ff.; (=504=) _ibid._, 2520; (=505=) _Cat. of Terracottas_, C 612; (=506=) _Cat. of Sculpt._, III., 2310; (=507=) _Cat. of Bronzes_, 357; (=508=) Cf. Pernice, _Griech. Pferdegeschirr_, pll. ii. and iii. (56th _Winckelmannsfestprogramm_); (=509=) _ibid._, pl. i. and pp. 6-16; (=510=) Cf. _Rev. Arch._, 1900 (36), p. 296 ff; Smith, _Dict. of Ant._^3, s.v. _Solea_. [Footnote 55: See _Journal of Hell. Stud._, xix., pl. 8.] [Footnote 56: _E.g._, on _B.M. Coins of Ionia_, pl. xx. 7 (Coin of Magnesia: Gordianus Pius).] [Footnote 57: Xen., _De re eq._ x. 6: [Greek: prôton men toinyn chrê ou meion duoin chalinoin kektêsthai; toutôn de estô ho men leios, tous trochous eumegetheis echôn, ho de heteros tous men trochous kai bareis kai tapeinous, tous d' echinous oxeis, hina hopotan men touton labê, aschallôn tê trachytêti dia touto aphiê].] [Footnote 58: _De re eq._ v. 3.] [Footnote 59: Xen., _op. cit._, iv. 3.] [Footnote 60: Thuc., vii. 27, 5.] [Footnote 61: Suet., _Ner._ 30.] XVII.--AGRICULTURE. (Wall-Case 52.) Farming, the rearing of live stock, the cultivation of corn, vines and olives were practised by the earliest civilisations of the Aegean, and of Greece.