In 1889, a pizza-maker by the name of Raffaele Esposito created “Pizza Margherita” to honour the Queen consort, who was referred to as “Margherita of Savoy”. Supposedly, he garnished it with tomatoes, cheese and basil in honour of the Italian flag.

I learned about this fact from: http://en.wikipedia.org/wiki/History_of_pizza#cite_note-amherit-16