The sixteenth century brought increased English military occupation and settlement to Ireland. Members of the invading nobility, who consequently came into contact with the native culture, were seduced by the sound of the Irish harp and took the instrument from its roots in Gaelic society and placed it in the setting of European courtly music. My aim is to examine this process, the resulting developments which took place in the evolution of the Irish harp, and compositions associated with its usage in the 'art' music of England and the Continent. Particular reference is made to the 'Harpe' Consorts of William Lawes together with their sources and resulting implications when considering the capabilities of the instrument employed. The harp's role within this music is also analysed and a complete set of transcriptions of Lawes' consorts is included. Works by other musicians associated with the Irish harp during the period 1550-1650 are also discussed with specific reference to the compasses and accidentals of the instruments required by the composers where appropriate. Transcriptions of works attributed to Cormack MacDermott and the anonymous harp parts located at the back of Ch Ch Mus MS 5 are included. Martin Peerson's 'Mottects or Grave Chamber Music' and a collection of works for 'Treble Bass Viol and Harp', included in the back of the 1687 edition of Christopher Simpson's A Compendium of Practical Music are also discussed. A major part of the research involved the reconstruction of an Irish chromatic harp (presented as part of this thesis) capable of playing the music examined. An account of this is given in a report which looks at the decisions and processes involved, difficulties encountered, as well as some recommendations for future experimental directions.