The most common system of length measures used in Portugal in the Middle Ages was the craveiro system, based on the palm, which amounted to about 22 cm.

There are two main multiples of the palm: the côvado, also known as alna, amounting to 3 palms and the vara, amounting to 5 palms.

Each of these measures had a submultiple of half of its size: the half-côvado and the half-vara.

There were also other systems with different côvados and varas and other measures, such as the braça used less commonly than the others and the half-braça. Most authors consider that the braça would have been twice the vara, which would make it 220 cm, although there are those who believe it could be about 184 cm.