The Central Middle Ages (1100-1350) - Period overview and biographies of individual composers of early music complementing Here Of A Sunday Morning the radio program.
Medieval Music - Wikipedia article providing an overview of the period with summaries of musical developments plus internal references to related people and topics and external links.
Medieval Period (1200 - 1450) - Introduces those responsible for developing harmony and added instrumentation to Western music. From The Conservatory at Humanities Web.
Medieval, Renaissance, and Traditional Music - Collection of MIDI audio files freely downloadable from Kunst der Fuge. Sorted by nationality and author.
The Medieval Sound - David Munrow - CD - Introduction and demonstrations of individual medieval instruments, followed by suites of Renaissance and Elizabethan dances.
Middle Ages: 450-1450 - Introduction to the Medieval Era from Essentials of Music linked to details on historical themes, musical context, style, and composer biographies.
Music History 102: The Middle Ages - Composers, major styles and developments, illustrations, and Real Audio RAM sound files from the Internet Public Library.