Put the following composers in order form earliest to latest.
guillaume de machaut
léonin
john of forneste
pérotin

Léonin

Pérotin

John of Forneste

Guillaume de Machaut

Explanation: Guillaume de Machaut lived in the 1300

Léonin lived in the mid 1100 until the start of the 1200

John of Forneste lived in the mid 1100, and died in the 1239

Pérotin was born aroun 1160, and died in 1230

Bassed on this, the list from earliest to latest would be:

Léonin, Pérotin, John of Forneste, Guillaume de Machaut

answer; isometric perspective;

your word would be isle.

isle is an island or peninsula especially a small one.

if you add the letter "a" you get aisle, which is a passage between 2 rows of something like chairs, shelves, or something else.