Laetetur Ierusalem
Source: Guido Maria Dreves and Clemens Blume, eds., Analecta Hymnica Medii Aevi, Vol. 45b. Cantiones et Motetten des Mittelalters (Leipzig: O. R. Reisland, 1904), pp. 133-4, #164, De Nativitate Dominio.
1. Laetetur Ierusalem, Sion plaudat filia, Nam Christus in Bethlehem Natus est a filia; Pax in terra comminus, Lux in nocte claruit, Rex et regum Dominus Mundo dum apparuit. 2. In caelorum sedibus Regnat et hic cernitur, Irrigatur fletibus, Heu, a multis spernitur; Ibi felicissimus In supernis colitur, Hic vero mitissimus In praesaepe ponitur. 3. Exsultarunt angeli Nato Dei filio, Exsultemus singuli In isto exsilio, Nam humano generi Salus et redemptio Ortus salutiferi Venit ab initio. 4. Ipse fecit hominem Et eum paenituit Atque fudit sanguinem Et peccata abluit ; Pneumati paraclito Detur laus et gloria, Cum patri et filio Per aeterna saecula. R ° In Mariae filio Nostra gaudet contio, In hoc ipso parvulo Salvatore Domino.
Dreves notes:
Piae Cantiones 1582 fol. B 3 b. [Klemming II, 31 ff. ais “Hymnus”.) —
1, 4 est a familia. —- 2, 3 Mitigatur. 
Also found in G. E. Klemming, ed., Piae Cantiones. S. Trinitas. Iesus Christus. S. Spiritus. S Maria (1886), pp. 31-33. Primary source for many scholars, including Dreves, Woodward and others.
Some sources of Latin hymns found in Piae Cantiones:
Guido Maria Dreves and Clemens Blume, eds., Analecta Hymnica Medii Aevi, Vol. 1. Cantiones Bohemicae. (Leipzig: O. R. Reisland, 1886).
Guido Maria Dreves and Clemens Blume, eds., Analecta Hymnica Medii Aevi, Vol. 45b. Cantiones et Motetten des Mittelalters. (Leipzig: O. R. Reisland, 1904).
George Ratcliffe Woodward, Piae Cantiones: A Collection of Church & School Song, chiefly Ancient Swedish, originally published in A.D. 1582 by Theodoric Petri of Hyland. (London: Chiswick Press for the Plainsong & Medieval Music Society, 1910).
Sheet music for some hymns can be found in George Ratcliffe Woodward, The Cowley Carol Book, First & Second Series. Table Of Contents. (London: A. R. Mowbray & Co., Ltd., ca. 1902, 1912).
Translations of some carols can be found in John Mason Neale and Thomas Helmore, eds., Carols for Christmas-tide (London: Novello, 1853). By the same authors was Carols for Easter-tide (1854).
Translations and sheet music for some hymns can be found in Charles L. Hutchins, ed., Carols Old and Carols New (Boston: Parish Choir, 1916).
Scans of individual pages from Pić Cantiones (in the Adobe PDF format) can be downloaded from Facsimiles Piae Cantiones (http://www.spielleut.de/facs_piae_cantiones.htm; accessed June 15, 2009).
