There were many different systems and methods of historical Spanish swordsmanship, but they can be divided into three very broad categories - the old school, the true school (based on geometry), and the late school (predominantly foreign influence). There can be a great deal of difference between methods in a given category, and many are a blend of categories that represent a transition from one to another in various degrees. Still, these groupings help us understand major changes in Iberian swordsmanship over time.
Old School
These methods were the first developed in Iberia (now Spain and Portugal) and lasted into the 18th century. The earliest known authors are Jaime Pons and Pedro de la Torre, both writing in 1474, but records of maestros (masters) and examinations go back much further. Many different weapons were used, including the sword alone, two-handed sword/montante, sword and round shield, buckler, dagger, cloak, two swords, dagger alone, spear, half-spear, stick, axe, and halberd. It was simply called esgrima (fencing/swordsmanship), until proponents of the "true" style began to refer to it variously as esgrima común (common fencing), esgrima vulgar (vulgar fencing), esgrima antigua (old fencing), destreza ordinaria (ordinary skill), destreza antigua (old skill), and destreza falsa (false skill). The only complete treatise of this style that has been located is Arte de Esgrima (Art of Fencing), written in 1599 by Domingo Luis Godinho. Combined with references made by other authors, this forms the basis of our knowledge about the old style.
True School
These methods began with the first publication of Jeronimo Sanchez de Carranza, at the end of the 16th century. Its authors refer to it as la verdadera destreza (the true skill), though others sometimes refer to it as the mathematical play, due to its use of geometry and Aristotelian physics to analyze fencing actions. Through precepts and mathematical demonstrations, it would determine which actions were "true" and which were "false," although various authors disagreed on exactly which actions they considered to be true, resulting in various methods. The most prolific author, Luis Pacheco de Narvaez, parted from Carranza in his later works. He, along with Francisco Antonio de Ettenhard and Francisco Lorenz de Rada, are the authors that had the most influence on the development of la verdadera destreza. It focuses almost exclusively on the sword alone, with occasional commentary on incorporating companion arms or the montante, and lasted in some form into the 19th century.
Late School
Although there had always been interaction with foreign swordsmen and adaptation to their methods, political changes in the 18th century caused a cultural shift which led to the adoption of foreign styles of fencing (mainly French and Italian). The small sword and sabre became fashionable, and these new methods were incorporated into la verdadera destreza at first. Eventually, the new methods replaced it altogether.