derive from a combination of the Greek character "psi" (ψ) and "S". Writer Ayn Rand claimed in her 1957 book Atlas Shrugged that the sign started off as a monogram of "US", with a narrow "U" superimposed on the "S", which would have been used on money bags issued by the United States Mint. In her theory, the bottom part of the "U" would have been lost, producing the dollar sign with two vertical lines. Authors T. Seijas and J. Frederick noted that the captors of slaves in Spanish territories sometimes branded enslaved people with a symbol very similar to a one-barred dollar sign. Esclavo is Spanish for "slave," and clavo means nail. A dollar sign is S + clavo. A theory often cited in Portuguese speaking countries is that the "S" part of the doubly-stroked sign is a schematic representation of the path followed by the Umayyad Caliphate general Tariq Ibn Ziyad in his conquest of the Visigoth kingdom in 711 CE, and the two strokes represent the Pillars of Hercules that he would have crossed along that path. That symbol would have been engraved in coins commemorating his victory, and then became symbolic of currency in general. Currencies that use the dollar sign As symbol of the currency The numerous currencies called "dollar" use the dollar sign to express money amounts. The sign is also generally used for the many currencies called "peso" (except the Philippine peso, which uses the symbol "₱"). Within a country the dollar/peso sign may be used alone. In other cases, and to avoid ambiguity in international usage, it is usually combined with other glyphs, e.g. CA$ or Can$ for Canadian dollar. The dollar sign, alone or in combination with other glyphs, is or was used to denote several currencies with other names, including: Brazilian cruzeiro (various currencies, all defunct): ₢$, , , , etc. Brazilian real: R$ Ethiopian birr (until 1976): E$ Macanese pataca: MOP$ Nicaraguan córdoba: C$ Samoan tālā (a transliteration of the word dollar): $ Tongan paʻanga: T$ Malaya and British Borneo dollar (1957–1967): $ Malaysian ringgit (1967–1997): $, Prefix or suffix In the United States, Mexico, Australia, Argentina, New Zealand, Hong Kong, Pacific Island nations, and English-speaking Canada, the sign is written before the number ("$5"), even though the word is written or spoken after it ("five dollars", "cinco pesos"). In French-speaking Canada, exceptionally, the dollar symbol usually appears after