The first building used as a church at the Plymouth colony was the fort, and to it the Pilgrim fathers and mothers and children walked on Sunday reverently and gravely, three in a row, the men fully armed with swords and guns, till they built a meeting-house in 1648. In other New England settlements, the first services were held in tents, under trees, or under any shelter. The settler who had a roomy house often had also the meeting. The first Boston meeting-house had mud walls, a thatched roof, and earthen floor. It was used till 1640, and some very thrilling and inspiring scenes were enacted within its humble walls. Usually the earliest meeting-houses were log houses, with clay-filled chinks, and roofs thatched with reeds and long grass, like the dwelling-houses. At Salem is still preserved one of the early churches. The second and more dignified form of New England meeting-house was usually a square wooden building with a truncated pyramidal roof, surmounted often with a belfry, which served as a lookout station and held a bell, from which the bell-rope hung down to the floor in the centre of the church aisle. The old church at Hingham, Massachusetts, still standing and still used, is a good specimen of this shape. It was built in 1681, and is known as the "Old Ship," and is a comely and dignified building. As more elegant and costly dwelling-houses were built, so were better meeting-houses; and the third form with lofty wooden steeple at one end, in the style of architecture invented by Sir Christopher Wren, after the great fire of London, multiplied and increased until every town was graced with an example. In all these the main body of the edifice remained as bare, prosaic, and undecorated as were the preceding churches, while all the ambition of both builders and congregation spent itself in the steeple. These were so varied and at times so beautiful that a chapter might be written on New England steeples. The Old South Church of Boston is a good example of this school of ecclesiastical architecture, and is a well-known historic building as well.