Answer by taking a quote from the following article:

The term "Moors" refers primarily to the Muslim inhabitants of the Maghreb, the Iberian Peninsula, Sicily, and Malta during the Middle Ages. The Moors initially were the Berber autochthones of the Maghreb. The name was later also applied to Arabs. Moors are not a distinct or self-defined people, and the 1911 Encyclopaedia Britannica observed that "The term 'Moors' has no real ethnological value."

Moors--or more frequently their heads, often crowned--appear with some frequency in medieval European heraldry, though less so since the Middle Ages. The term ascribed to them in Anglo-Norman blazon (the language of English heraldry) is maure, though they are also sometimes called moore, blackmoor, blackamoor or negro. Maures appear in European heraldry from at least as early as the 13th century, and some have been attested as early as the 11th century in Italy, where they have persisted in the local heraldry and vexillology well into modern times in Corsica and Sardinia.  Armigers bearing moors or moors' heads may have adopted them for any of several reasons, to include symbolizing military victories in the Crusades, as a pun on the bearer's name in the canting arms of Morese, Negri, Saraceni, etc., or in the case of Frederick II, possibly to demonstrate the reach of his empire. The arms of Pope Benedict XVI feature a moor's head, crowned and collared red, in reference to the arms of Freising, Germany. In the case of Corsica and Sardinia, the blindfolded moors' heads in the four quarters have long been said to represent the four Moorish emirs who were defeated by Peter I of Aragon in the 11th century, the four moors' heads around a cross having been adopted to the arms of Aragon around 1281-1387, and Corsica and Sardinia having come under the dominion of the king of Aragon in 1297. In Corsica, the blindfolds were lifted to the brow in the 18th century as a way of expressing the island's newfound independence.  The use of Moors (and particularly their heads) as a heraldic symbol has been deprecated in modern North America. For example, the College of Arms of the Society for Creative Anachronism urges applicants to use them delicately to avoid causing offence.

What were other reasons for adopting the moors heads?
pun on the bearer's name in the canting arms of Morese, Negri, Saraceni, etc., or in the case of Frederick II,