Final answer:
Leonin and Perotin were influential composers from France, associated with the Notre Dame school and the development of Western music during the Medieval period.
Step-by-step explanation:
Leonin and Perotin were from the region of France, specifically in connection with the Notre Dame school of polyphony during the Medieval period. These composers were notable for their innovations in musical composition, particularly in the development of rhythm and meter which were crucial to the development of Western music. Their contributions are often studied within the broader context of the Ars Antiqua period, and their work reflects the vibrant cultural and intellectual life of Paris during the 12th and 13th centuries.