Drexel 4180–4185 is a set of six manuscript partbooks copied in Gloucester, England, containing primarily vocal music dating from approximately 1615-1625.

Based on inscriptions in the two manuscripts in the British and Bodleian libraries, Pamela Willetts observed that Merro had an interest in theology.

Such an indication is lacking in Drexel 4180–4185 suggesting that the partbooks were not part of Merro's personal collection but used by the cathedral, "made for informal use of choirmen and their friends.

[7] However, Rimbault, who printed some of the works in his A Collection of Anthems for Voices and Instruments by Composers of the Madrigalian Era, included the following note observing the now-lost bindings in that volume's preface: This valuable set of ancient Part-books consists of six small oblong volumes in the original binding, and with the Arms and Badge of Edward the Sixth stamped on the sides … The writing commences in the reign of Edward the Sixth, and ends in that of Charles the First, the last composition entered being an Ode composed by Orlando Gibbons for the marriage of that king with the princess Henrietta Maria.

[7] The physical layout of music resembles that of the manuscripts Christ Church MSS 984-8 (The Dow Partbooks) and British Library Add MS 22597.

This might have been a conscious decision on Merro's part to acknowledge the music's historic nature by maintaining the appearance of an archaic manuscript.

From whom he obtained the partbooks is revealed by the title of the publication in which he printed a few of the selections: A Collection of Anthems for Voices and Instruments by Composers of the Madrigalian Era Scored From a Set of Ancient M.S.

[16] The opening line of Rimbault's preface reads: The following collection of anthems by Este, Forde, Weelkes, and Bateson, have been scored from a manuscript set of part-books formerly in the possession of the celebrated John Evelyn, and now forming one of the many musical rarities in the library of the Editor.

Monson notes that while some of Merro's scribal characteristics remain consistent through the six partbooks (the writing of treble, bass and c-clefs), other details differ both in music and in text underlay and the way in which they are written.

[22] He notes that works by Byrd included in the collection appear to be written in a more archaic style, describing it as "a gesture towards decorum in penmanship and towards a historical sense which he [Merro] seems to possess.

[11] Despite variances, Monson felt that Merro was the sole copyist of the six partbooks and that the changes are due to his writing the books over the course of a dozen years.

Acknowledging the popularity of Weelkes and Wilbye, Monson was struck by the lack of any works by Thomas Morley in Merro's collection.

Monson hypothesized that Merro must have had access to the three volumes of Gemmae Musicalis (published in 1588, 1589, and 1590) which would be the explanation for inclusions of the works on leaves 139v-149r.

[24] The two isolated Italian madrigals, "Dolorosi martir" by Marenzio and Tutt'eri foco by Pallavicino were apparently entered as afterthoughts on what were blank leaves.

Merro copied these motets at a time when the composers had been dead for several decades which can explain why many are listed anonymously or have incorrect attributions.

[25] Viewed as a whole, Merro's solo consort song repertory appears retrospective and antiquated (Monson calls it "ancient").

Two works by Michael East, "When Israel came out of Egypt" and "Sing we merrily" are not copied from the printed editions (which appeared in 1610 and 1624 respectively) but from earlier manuscript versions in secular sources.

"[27] Merro's version of Gibbons's "The London cry" differs from the one printed roughly contemporaneously in Thomas Myriell's "Tristitiae Remedium" (1615).

Though text underlay of these cry works were subject to variation, Merro's copy in Drexel 4180 is particularly extensive and occasionally explicit.

[30] Beginning on 158v of 4180 ("O sing unto the Lord" by Amner) is a final group of full anthems, haphazard mixture of five- to twelve-parts.

[11]) Merro was constrained by the organization of Drexel 4180–4185, so when he came up to William Randall's 6-part "Give sentence with me," he could not enter it after 167v so he went back and inserted it on half of 122v.

[31] Monson makes note of Thomas Bateson's seven-part "Holy Lord God almighty," his only extant sacred work.

Rather than be cross at the willful destruction of such leaves embedded in old bindings, Fallows asserted that we should be thankful to the collectors who sought to decorate their books using these otherwise discarded fragments.

[35] Of these nine fragments (some of which contain more than one composition), Stevens counted fifteen separate works, four which appear in the British Library manuscript Add.

[33] Although the original binding was lost when NYPL rebound the partbooks in 1950, some information can be ascertained based on the Bodleian fragments.

The Bodleian Day Book for 1613-1620, a log of daily happenings at the library, recorded that it was sent to the binder John Adams on October 2, 1615, confirmed by the type of binding used from 1615 on.

Departing from Stevens's point of view Fallows recognizes that the original leaf would have been the verso (now lost) facing fragment B.

The recto contains the end of a carol celebrating the wedding of James IV of Scotland to Margaret (Henry VIII's daughter) in 1503.

Fallows concludes with the hope for editions of unpublished music which will move knowledge toward a clearer understanding of the history of English song.

Stevens's list eschews use of bibliographic terms in identifying whether a fragment is recto or verso, or whether it comes from the front or the back of a volume.