Simple and universal, Marco is a Latin classic that would make a much livelier namesake for an Uncle Mark. It was used for her son by actress Jill Hennessy, and goes well with any straightforward surname.
Marco, related to the Roman god Mars, has long been associated with Marco Polo, the thirteenth century Venetian merchant-traveler who was instrumental in introducing Europeans to Asian culture. Eugene O'Neill wrote a play called "Marco Millions," based on the life of Marco Polo.
More recent noteworthy Marcos are Marco Andretti, Indy race car driver grandson of the legendary Mario, and Marco Rubio, Florida senator, and the name can also be found in two early Dr. Seuss books.