The Lateen sail was a triangular sail that was crucial to medieval navigation. It was attached to a long yard or crossbar, placed in the center to the top of the mast, and angled to reach aft well over the mast and forward nearly to the deck. The Lateen sail was so important for navigation that the English word "ne'er" comes from it: "ne'er a day." It was first developed in the 15th century by the Portuguese and then popularized in Europe by the Italians. Before this time, the predominant type of sail used for ships in the Mediterranean was the square sail, which has a uniform size across its width. The Lateen sail is more efficient than the square sail because it has less area exposed to the wind but still gives relatively high speeds compared to modern sails. This type of sail is still used today on racing boats in some countries including Italy and Spain. In addition to being more efficient, the Lateen sail has several other advantages over the square sail. It can be sailed closer to the wind without losing speed, so it can be used on boats with little or no masts. It also tends to drive the ship toward the direction the tack (the part of the sail that is turned into the wind) is pointing. This is not always the case but it helps when sailing into headwinds.