"Notwithstanding, as a dog hath a day, so may I perchance have time to declare it in deeds." [Queen Elizabeth, 1550]
"It is ill wakyng of a sleapyng dogge." [Heywood, 1562]Phrase to put on the dog "get dressed up" (1934) may refer back to the stiff collars that in the 1890s were the height of male fashion, with ref. to dog collars. The common Sp. word for "dog," perro, also is a mystery word of unknown origin, perhaps from Iberian.