Moorish heads in heraldry developed in Germany through the direct contact of the Germanic rulers of Italy with the Saracens.
Source: FEAR OF BLACKNESS SERIES: Guide to the Ethnic Origins of the “Infernal” and “Black Saracen”

“The Victoria and Albert Museum in London states, “The king of Sicily Frederick II born in 1194, in fact, took a keen interest in the black Muslim population that had remained in Sicily after the island’s return to Christian rule in 1061. He established an enclave for these Muslims near his palace in Lucera in southern Italy, and recruited his musicians and elite bodyguard from the community.” It is the Hohenstaufan dynasty to which he belonged that actually used the Moors or Saracen head as a symbol of their dynasty. Hohenstaufen or Stauf Castle of southern Germany was built by these “Saracens” under Frederick I.”
Source: Africans in Medieval & Renaissance Art: The Moor’s Head
The Victoria and Albert Museum provides, “The moor’s head device was also used in Italian heraldry, especially by families in the north and centre of the peninsula. The earliest known example appears in the 11th century.”
Source: Africans in Medieval & Renaissance Art: The Moor’s Head

According to Dana Reynolds Marniche:

“It was used by the Saraceni family of Siena, the Morandi of Genoa, the Morese of Bologna, the Negri of Vicenza and the Pagani of Saluzzo” to name a few. The museum suggests that it may have been used as a pun and that the families were founded by crusaders. It may be also that the Saracens who fought with the Christians and/or Muslims that served Frederick who was Holy Roman Emperor founded such families as well. It is of course well- known that some of the earliest black Saints in European history were Muslim Moors that had turned Christian. In any case, the fact that the usage of the Moorish or Saracen head dates back to the exact time the Moors were in Italy and Corsica, rules out the idea that the first Germanic peoples who used them just imagined Moors and Saracens were jet black.”
Source: FEAR OF BLACKNESS SERIES: Guide to the Ethnic Origins of the “Infernal” and “Black Saracen”
Sophia Arjana wrote,
“Dark-skinned Muslims found in medieval plasters, paintings, poetry and romances are not always monstrous, but their blackness indicates that they are evil…The monster that encapsulated all three of these entities – Saracen, Jew, and black African – is the Black Saracen. This is a hybrid monster, an African (implicated as Satan by his dark skin), Jewish (depicted executing a saint), and Muslim (by the monker “Saracen” as well as by the turban he often wears)”(Arjana, 2014, p. 49).
Source: FEAR OF BLACKNESS SERIES: Guide to the Ethnic Origins of the “Infernal” and “Black Saracen”
In a poem called Coeur de Lyon dealing with the Third Crusade of Richard “the Lion-heart” against Saladin’s forces in the late 12th century Levant the king is fed the head of a fat “Saracen”. According to Geraldine Chen author of “Empire of Magic” at one point in the first chapter of “the Coeur”, while the king is being fed the narrative “zeroes in on the black face and black beard of the detached head set off against white teeth that are bared by widely grinning lips…”
An additional ballad states, “Marko Kraljevic and the daughter of the Moorish king”, Marko tells his mother that he was once in the land of the Moors where he smote many of them, but at one point he was cast into a dungeon where he was desired by the daughter of the Moorish king. He says he was tormented by the daughter of the king who would come to him morning and night calling through the dungeon window, telling him not to cry, but begging and bribing him to give her his solemn word that he will marry her and she would see that he go free from his prison. Then Marko agreed and she let him out giving him back his sword, and they went away “through the land of the Moors on horseback.” Marko then tells his mother that when one day at dawn “the Moorish maiden took me, Encircling me with her black arms”, and when he looked upon her -“On her black face and white teeth” a “loathing” took hold over him and and he “drew the rich-sabre and smoteher on the silken girdle.” After this the severed head of the Moorish woman had the audacity to call out to him in desperation“‘Brother in God Kraljevic Marko! Leave me not ! Leave me not!” (p. 106)
Source: The English and Scottish Popular Ballads

“The comparatively small number of iconographic documents so far discovered does not allow us to draw conclusions. Thus, unexpectedly, we note the apperance of the heraldic Moor (a ribbon with fluttering ends is tied around his head) in the field of watermarks. C.M. Briquet, Les filigances Dictionnarie historique de marques du papier des leur apparition vers 1282 jusquen 1600, 4 vols. (Paris 1907), presents a large number of such devices. (A facsimile edition of this work was done in recent years: see The New Briquet, ed. A. Stevenson, 4 vols. [Amsterdam, 1968].) The oldest watermarks seem to represent a human head with no ethnic characteristics, but those numbered 15.589 and 15.590 form a transition from the early style to a group (nos. 15.591-15.638) in which the Moor’s head generally is recognizable.Watermarks nos. 15.591 through 15.628 seem to be of Italian origin; according to C.M. Briquet, nos. 15.629-15.638 originated in Piedmont or in the south of France. The whole group dates from between 1380 and 1460; see Briquet, Les Filigrances, vol. IV, pp. 780, 789-90.”


“A survery focusing on such eponyms as “Moor,” “Negro,” and Saracen” gives no reason to suppose that canting arms with a black’s head or bust were more in favor in Tuscany than elsewhere in Italy. According to the work by G.B. di Crollalanza, Dizionario storico-blasomico delle famiglie nobili e notabili italiane esinte e fiorenti,3 vols. (reprint ed., Bologna, 1977 [1886-1890]), northern Italy seems to have been more disposed to this usage. By way of evidence, here are the dates of the first mentions of noble families with canting arms, as given by G. B. Crollalanza; eleventh century, Morici di Assissi; 1154, Saraceno di Matera; 1170, Morandi di Genova, 1212, Saracini di SIena; 1265, Morese di Bologna; 1265, Negri di Vicenza (of Germanic origin); 1399, Pagani di Saluzzo; 1404, Saracino di Verona; 1406, Negrina di Verona; 1421, Mori di Cesena; 1430, Negri di Bologna. We might note particularly the importan place occupied by the Saracini in Siena; for instance, their shield is found among those of the city magristrates on the painted boards of the tax records (Gabella) for the years 1471, 1479, 1485 and 1489, now in Siena, Archivo di Stato; see E. Carli, Les tablettes peintes de la “Biccherna” et de la “Gabella” de l’anienne Republique de Sienne, Sphaera, vol. 5 (Milan and Florence, 1951), p. 38, no. 53 and pl. XXXIII; p.40, no. 56 and pl. XXXVI; pp. 44-45, no. 60 and pl. XL; p. 47, no. 63 and pl. XLIII.”


.
“In the course of our investigation we came across the arms of Jacop Silvestri di Norcia on a bas-relief embedded in the wall of the Museo Nazionale del Bargello in Florence, inv. no. 55; these arms, dated 1448, have a bust of a Moor in the crest. We also encountered a Moor’s head in the crest of the arms of the Talani family of Florence, which were painted on a wedding chest dating from the first half of the fifteenth century, now in Florence, Museo dell’Antica in the Palazzo Davanzali, iv. no 178; see L. Berti, II Museo di Pazzo Davansali a Firenze, Gallerie e Musei di Firenze (Milan, 1971[?]), p. 205, no. 75 and pl. 50.”


“Nor can the Moors of heraldry be explained sufficiently by the theory that the founders of families bearing Moors as supporters, and Moors’ heads as crest, had won their spurs in assisting the Spaniards to expel their Moors. The bearing is too common among ancient coats to admit of this explanation. And the heraldic representation of a “Moor or Negro-man” does not suggest Granada. The features are ugly and irregular, and the hari, though longer than that of a pure negro, is wooly. The head is encircled by a fillet or chaplet, and there are “pearls pendant” from the ears. The complexion is, of course, black. Such men are indifferently styled “Moors” and “Saracens.” Their prescence in the armorial bearings of ancient families can only be due to the cause which mad “savages,” ” wild-men,” or “wood-men” so common among shields,–the exploits of the founder of the family in the long conflicts with the people of “Heathenesse.”

Source: Ancient and Modern Britons: A Retrospect, Volume 1 By David MacRitchie
“The legend of the Moorish head goes back in the XI century, during the Moors domination in Sicily and as in most legends, is once again Cupid’s fault (or credit). One day, a beautiful and honorable young girl living in the Kalsa, the arabic district of Palermo, was taking care of plants and flowers in the balcony of her house as she was used to. Suddenly, a Moor merchant who was passing by, fell in love with the beautiful girl who immediately returned his love. They started having a love story until when she discovered he already had a wife and children waiting for him in his native land. She went suddenly crazy of jealousy and one night, while he was sleeping she thought of a way to make him stay with her forever! She therefore cut off his head and cleverly decided to use it as a vase to grow her beautiful basil plant. People walking down her balcony started looking at her flourishing plant of basil and became jealous of how bloomed her plants were, so they began to forge colourful clay heads pots wishing to have the same magic green thumb.”