 Medieval pie crusts were often baked first, to create a "pot" of baked dough with a removable top crust, hence the expression "pot pie".The first unequivocal reference to pie in a written source is in the 14th century ("Oxford English Dictionary" sb "pie").The eating of mince pies during festive periods is a tradition that dates back to the 13th century, as the returning Crusaders brought pie recipes containing "meats, fruits and spices".