Add MS 29987 is a mediaeval Tuscan musical manuscript dating from the late fourteenth or early fifteenth century, held in the British Library in London. It contains a number of polyphonic Italian Trecento madrigals, ballate, sacred mass movements, and motets, and 15 untexted monophonic instrumental dances, which are among the earliest purely instrumental pieces in the Western musical tradition. The manuscript apparently belonged to the de' Medici family in the fifteenth century, and by 1670 was in the possession of Carlo di Tommaso Strozzi; it was in the British Museum from 1876, where it was catalogued as item 29987 of the Additional manuscripts series. It is now in the British Library. The manuscript The manuscript appears to have belonged to the de' Medici family of the Republic of Florence in the fifteenth century – the first folio has the de' Medici arms in red, gold, blue and green; these are in the "augmented" form granted by Louis XI in 1465, with the arms of France in the upper central ball. By 1670 it was in the possession of Carlo di Tommaso Strozzi. On 8 April 1876 it was acquired by the British Museum from the antiquarian bookseller Bernard Quaritch; it was catalogued as item 29987 of the Additional manuscripts series. It is now in the British Library. The manuscript measures approximately , and consists of 88 parchment leaves in 11 quaternio gatherings. There are six flyleaves at the front, one from 1957, three from 1876 and two from the seventeenth century, of which the first has a list in the hand of Carlo di Tommaso Strozzi of the composers represented; two flyleaves at the back date from 1876 and 1957. The binding in half leather is from 1957, over older thick wooden boards. Add 29987 is a part of a larger manuscript of at least 185 pages, as the surviving leaves were originally numbered 98–185. The pages are ruled with eight five-line staves in red, and the music is written in full (black) mensural notation, with only occasional use of void ("white") notes and red colouration. It is carelessly written in one principal and several other scribal hands; the musical text is corrupted in many places by a later hand, which altered the rhythms and added inappropriate rests. The exact date of the manuscript remains uncertain; estimates range from the late fourteenth century to about 1425. The music dates from