instrument such as the lute, vihuela, harp, or keyboard. Such arrangements were called intabulations (It. intavolatura, Ger. Intabulierung). Towards the end of the period, the early dramatic precursors of opera such as monody, the madrigal comedy, and the intermedio are heard. Theory and notation According to Margaret Bent: "Renaissance notation is under-prescriptive by our [modern] standards; when translated into modern form it acquires a prescriptive weight that overspecifies and distorts its original openness". Renaissance compositions were notated only in individual parts; scores were extremely rare, and barlines were not used. Note values were generally larger than are in use today; the primary unit of beat was the semibreve, or whole note. As had been the case since the Ars Nova (see Medieval music), there could be either two or three of these for each breve (a double-whole note), which may be looked on as equivalent to the modern "measure," though it was itself a note value and a measure is not. The situation can be considered this way: it is the same as the rule by which in modern music a quarter-note may equal either two eighth-notes or three, which would be written as a "triplet." By the same reckoning, there could be two or three of the next smallest note, the "minim," (equivalent to the modern "half note") to each semibreve. These different permutations were called "perfect/imperfect tempus" at the level of the breve–semibreve relationship, "perfect/imperfect prolation" at the level of the semibreve–minim, and existed in all possible combinations with each other. Three-to-one was called "perfect," and two-to-one "imperfect." Rules existed also whereby single notes could be halved or doubled in value ("imperfected" or "altered," respectively) when preceded or followed by other certain notes. Notes with black noteheads (such as quarter notes) occurred less often. This development of white mensural notation may be a result of the increased use of paper (rather than vellum), as the weaker paper was less able to withstand the scratching required to fill in solid noteheads; notation of previous times, written on vellum, had been black. Other colors, and later, filled-in notes, were used routinely as well, mainly to enforce the aforementioned imperfections or alterations and to call for other temporary rhythmical changes. Accidentals (e.g. added sharps, flats and naturals that change the notes) were not always specified, somewhat as in certain fingering notations for guitar-family instruments (tablatures) today. However, Renaissance musicians would have