Complex sentence: The economy of England in the Middle Ages, from the Norman invasion in 1066, to the death of Henry VII in 1509, was fundamentally agricultural, though even before the invasion the market economy was important to producers.
Split into simpler sentences: The economy of England in the Middle Ages encompasses the economic history of England from the Norman invasion in 1066, to the death of Henry VII in 1509. England's economy was fundamentally agricultural throughout the period, though even before the invasion the market economy was important to producers.