Ptolemy assigns Aldebaran the nature of Mars in the Tetrabiblos, Book I chapter 9, where he goes through the notable fixed stars and gives each a planetary temperament. The reasoning for Aldebaran is not stated but is evident from the pattern: Ptolemy consistently reads the visibly red stars as martial, and gives the same treatment to Antares and to the red shoulder of Orion.
This is worth stating precisely because it is the strongest form of attribution available in this material. Ptolemy is a named author, in a datable second-century text that survives, making an explicit assignment. Most fixed-star attributions in circulation do not have that. Where a star has a Ptolemaic nature, it should be cited as Ptolemy's; where it does not, the source is later and usually much later.
The elaborated readings (honour, courage, eloquence and high office, held only through integrity, with a violent fall for those who fail), are not in Ptolemy. They come from the later compiling tradition, and in English overwhelmingly from Vivian Robson's The Fixed Stars and Constellations in Astrology of 1923, which assembled Ptolemy, Arabic material, Renaissance sources and nineteenth-century writers into a single reference. Robson's book is the proximate source of almost every fixed-star delineation printed in English since, and it is usually quoted without attribution.
Robson was a compiler and did not always distinguish his sources. Reading his entries as ancient tradition, when parts of them are Victorian, is the standard error with this material.
Aldebaran is one of Agrippa's fifteen Behenian stars, paired with ruby or garnet and with milk thistle.