Kathleen Schlesinger, 1911 Encyclopædia Britannica, Volume 12… (1911)
“ The construction of the instrument is of paramount importance in assigning to the guitar its true position in the history of musical instruments, midway between the cithara (i.e.) and the violin. The medieval stringed instruments with neck fall into two classes, characterized mainly by the construction of the body: (1) Those which, like their archetype the cithara, had a body composed of a flat or delicately arched back and soundboard joined by ribs. (2) Those which, like the lyre, had a body consisting of a vaulted back over which was glued a flat soundboard without the intermediary of ribs ”
