The act of marking livestock with fire-heated marks to identify ownership has origins in ancient times, with use dating back to theancient Egyptians. Among the ancient Romans, the symbols used for brands were sometimes chosen as part of a magic spell aimed at protecting animals from harm.
In English lexicon, the word “brand”, common to most Germanic languages (from which root also comes “burn”, cf. German Brand “burning, fire”), originally meant anything hot or burning, such as a “firebrand”, a burning stick. By the European Middle Ages, it commonly identified the process of burning a mark into stock animals with thick hides, such as cattle, so as to identify ownership under animus revertendi. The practice became particularly widespread in nations with large cattle grazing regions, such as Spain.
Thanks to Wikipedia.com for the text about branding.