Santa Maria do Olival stands at the edge of the old town, a sober Gothic church that appears older than it is — rebuilt in the thirteenth century on an earlier foundation, its unadorned façade gives little hint of its historical importance. For a provincial church it has played an outsized role: this was the burial place of several Masters of the Knights Templar and later the Order of Christ, and in the age of Portuguese exploration it served as the canonical mother church for all overseas territories claimed by the Portuguese crown.
The interior is simple and cool, with a nave flanked by side aisles and the usual Portuguese blue-and-white azulejo panels. The tombs of the Grand Masters are set into the floor — not the theatrical sarcophagi of great cathedrals, but flat slabs that you walk across, which lends a certain democratic intimacy to the dead. The tower on the façade has been around long enough to be slightly askew; it still reads the time in the old way, with a single hand.
Worth a brief visit, particularly if you are interested in the Templar history of the town. It lies about fifteen minutes' walk from the convent, downhill along the river.