There were many different plucked instruments that were being invented and used in Europe, during the Middle Ages. By the 16th century, most of the forms of guitar had fallen off, to never be seen again. However, midway through the 16th century, the five-course guitar was established. It was not a straightforward process. There were two types of five-course guitars, they differed in the location of the major third and in the interval pattern. The fifth course can be placed on the instrument because it was known to play seventeen notes or more. Because the guitar had a fifth string, it was capable of playing that amount of notes. The guitar's strings were tuned in unison, so, in other words, it was tuned by placing a finger on the second fret of the thinnest string and tuning the guitar bottom to top. The strings were a whole octave apart from one another, which is the reason for the different method of tuning. Because it was so different, there was major controversy as to who created the five course guitar. A literary source, Lope de Vega's Dorotea, gives the credit to the poet and musician Vicente Espinel. This claim was also repeated by Nicolas Doizi de Velasco in 1640, however this claim has been refuted by others who state that Espinel's birth year (1550) make it impossible for him to be responsible for the tradition. He believed that the tuning was the reason the instrument became known as the Spanish guitar in Italy. Even later, in the same century, Gaspar Sanz wrote that other nations such as Italy or France added to the Spanish guitar. All of these nations even imitated the five-course guitar by "recreating" their own.