Roma tomatoes are typically known as "saucing tomatoes". Their smooth shape make them easy to peel, and they have a high flesh to juice ratio, which lends itself well to cooking into a sauce with a great consistency.
Tomatoes originated from South America, where over 10 different varieties have been growing for thousands of years. Tomatoes are technically nightshade berries with an umami flavour. Cherry tomatoes are the descedants of wild tomatoes (which are normally the size of peas), and grape tomatoes are a more recent cultivar of cherry tomatoes. Grape tomatoes are a hybrid from Taiwan, and were first grown in North America in 1996. Andrew Chu, a tomato farmer in Manatee County, Florida, branded the name 'Grape Tomato' in 1998.