Originally conceived as an Italian attempt to revive the legionary swordsman, they were adopted by the Spaniards who used them with great efficiency. In addition to their shields, they often wore some form of helmet, and quilted or metal body armour covering the chest.
The majority of Cortez's troops during his campaigns in the New World were rodeleros: in 1520, over 1000 of his 1300 men were so equipped, and in 1521 he had 700 rodeleros, but only 118 arquebusiers and crossbowmen.
When the Spanish adopted the Colunella (the first of their mixed pike and shot formations), they used small groups of Sword and Buckler men to break the deadlock of the push of pike, as the Swiss and Germans used halberdiers. At the Battle of Ravenna (1512), they proved to be deadly at this tactic; however, when facing a fresh, undisordered pike square, they could be rolled over, such as at the Battle of Seminara. They were also very vulnerable to attack by cavalry.
The weaknesses of the Rodoleros were ultimately seen by the Spanish to outweigh their strengths, and they were dropped as a troop type when the Spanish infantry were reorganized into Tercios in the 1530s.
Occasional attempts were made to revive them, such as by Maurice of Nassau, who armed his guard troops with a sword and buckler in addition to a pike. Later during the Thirty Years War, some military theorists proposed deploying swordsmen equipped with large iron shields in front of the pikemen to protect them from being shot by enemy musketeers, but it is doubtful that this fanciful tactic was either successful or much employed in practice.