was there any controversy related to it?
Yes, scholars debate whether this was the reason for the emergence of Feudalism and its subsequent spread into Northern Italy, Spain, Germany and into the Slavic territories.
Stirrup
The introduction of the stirrup not only made the mounted warrior supreme in medieval warfare, but may have initiated complex and far-reaching social and cultural changes in Europe. Some scholars credit the birth of feudalism and its subsequent spread into Northern Italy, Spain, Germany and into the Slavic territories to this use of the stirrup. It is argued that the rising feudal class structure of the European Middle Ages derived ultimately from the use of stirrups: "Few inventions have been so simple as the stirrup, but few have had so catalytic an influence on history. The requirements of the new mode of warfare which it made possible found expression in a new form of western European society dominated by an aristocracy of warriors endowed with land so that they might fight in a new and highly specialized way."

Other scholars dispute this assertion, suggesting that stirrups may provide little advantage in shock warfare, but are useful primarily in allowing a rider to lean farther 
where is the smallest bone in your body located In the middle ear. does the bone have a name? Yes, stapes or stirrup. what is its function? It transmits sound vibrations from the incus to the oval window. what does the window mentioned above refer to? It is a membrane-covered opening from the middle ear to the cochlea of the inner ear. how did the smallest bone get its other name? Because of its resemblance to a stirrup. what does the term mean? It is a light frame or ring that holds the foot of a rider, attached to the saddle by a strap.
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Stirrup [SEP] Great Stirrup Controversy
The introduction of the stirrup not only made the mounted warrior supreme in medieval warfare, but may have initiated complex and far-reaching social and cultural changes in Europe. Some scholars credit the birth of feudalism and its subsequent spread into Northern Italy, Spain, Germany and into the Slavic territories to this use of the stirrup. It is argued that the rising feudal class structure of the European Middle Ages derived ultimately from the use of stirrups: "Few inventions have been so simple as the stirrup, but few have had so catalytic an influence on history. The requirements of the new mode of warfare which it made possible found expression in a new form of western European society dominated by an aristocracy of warriors endowed with land so that they might fight in a new and highly specialized way." Other scholars dispute this assertion, suggesting that stirrups may provide little advantage in shock warfare, but are useful primarily in allowing a rider to lean farther to the left and right on the saddle while fighting, and simply reduce the risk of falling off.