A single-nave church building with a single hall-like space is known as an aisleless church. While the aisleless church is similar to the hall church, it lacks aisles or passageways on either side of the nave and is divided from it by colonnades or arcades, a series of pillars or columns. However, there is sometimes no strong distinction between the various building up styles, also many churches have evolved over time from a mix of them. Since it was difficult to cover a wide, open space without using pillars or columns, early aisleless churches were typically small.
Former medieval hall churches were enlarged over the course of centuries in many areas where the population demanded it and capital was available, before they became hall churches.
The church hall’s basic shape is rectangular. The altar and choir are usually situated at one of the narrower ends of an aisleless church, facing east. There are a few examples of transept aisleless churches, in which the altar area is located on the transept’s short east side.
This form of church building has proliferated since the Renaissance, especially in Protestant churches. It became the basis of modern church architecture. In Norway, the aisleless and elongated “long church” is the most common design and is regarded as the typical Norwegian church. The Norwegian long church usually includes a narthex/vestibule in a separate section, often in a somewhat lower and narrower room attached to the main body and traditionally in the western end of the building. Until the 1940 about 850 of Norway’s 1300 churches were aisleless, these numbers does not include some 1000 perished stave churches many of which were aisleless. For instance Flesberg Stave Church for 500 years had a rectangular aisleless ground plan until it was expanded in 1735 by adding three arms to a cruciform aisleless shape.
Source: Wikimedia and Wikipedia. https://commons.wikimedia.org/wiki/Main_Page