Please answer the following question: Given the following context:  The identity of the donor has not been established, although a number of suggestions have been advanced over the last 200 years. Harbison suggests the work's small scale indicates that it functioned as a portable altarpiece rather than as a private devotional work, and thus was commissioned by or for a member of the clergy. Other art historians have argued that the donor may have been a Genoese merchant. This belief has been fed by the triptych's similarity to Giovanni Mazone's Virgin and Child altarpiece in Pontremoli, Tuscany, which may place it in the Italian region of Liguria at latest by the end of the 15th century. Damaged coats of arms on the inner frames have been linked to the Giustiniani family, known for establishing trade links with Bruges in the 14th and 15th centuries. If not commissioned by that family, historical record place the work at least in their possession by the end of the century. In the early 1800s, Frances Weale attempted to place Michele Giustiniani as the donor, however later historical research has been unable to verify his presence in Bruges around 1437, and he seems to have returned to Italy by 1430.Mid-twentieth century technical examination revealed the Giustiniani coats of arms may have been painted over an earlier heraldic design, perhaps as early as the 15th century, whose signifiance and history is now lost. Dhanens theorises that a member of the Giustiniani family may have established other associations with St. Michael and St. Catherine, advancing that they were a member of the Italian Rapondi family, whose trading house in Paris was named after St. Catherine. Their daughter, also named Catherine, married the Italian merchant Michel Burlamacchi (Bollemard in Flemish) from Lucca, who was active in Bruges. From this Dhanens theorises the piece was commissioned as a wedding gift for the couple. Documents show weavers in Wervik paid taxes to Catherine Rapondi and in September 1434, when Michele Burlamacchi was tax collector in that town, van Eyck received a stipend funded...  answer the following question:  What was the first name of the person that historical research has been unable to verify his presence in Bruges around 1437?
A:
Michele