Although alheira derives from alho ( garlic) and was once used to describe any sausage seasoned with it, not all present-day alheiras contain garlic, although it is still a common ingredient.
The type of sausage that became known as "alheira" was invented by the Jews of Portugal, who were given the choice of either being expelled from the country in 1497 unless they converted to Christianity. Those who converted but secretly retained their beliefs avoided eating pork, forbidden in Judaism; this put them at risk of being noticed not to hang sausages, traditionally made of pork, in their fumeiros (smokehouses). As a way to avoid attracting the attention of the Portuguese Inquisition or in rural areas the portuguese Christians they did make sausages, but with other meats, such as poultry and game, mixed with bread for texture. This recipe later spread amongst Christians.
Alheiras were traditionally grilled or roasted and served with boiled vegetables. Nowadays they are often fried and served with chips and a fried egg. They are often one of the cheapest items in restaurant menus, although those made with game can be expensive.
Although alheiras are typically associated with the city of Mirandela, the regions of Beira Alta and Trás-os-Montes are also famous for their alheiras.
Varieties with PGI protection status include Alheira de Vinhais and Alheira de Barroso- Montalegre.