According to The Samosa Connection, the popular stuffed pastry came to India from Central Asia on ancient trade routes. The Food Lover's Companion notes that samosas are most often served as appetizers in East Indian restaurants.
Although the Indian variation is the most well-known, The Oxford Companion to Food says that the samosa belongs to a much larger family of such pastries that includes the Arab sanbusak. Variations are also found in East Africa and even West China. References to the samosa exist in Arabic cook books from the 10th and 13th centuries. The Samosa Connection also notes the existence of a 9th century Arabic poem that praises the pastry.