The grey-stone church of Ärentuna was built around the year 1300. It was probably inaugurated in 1302, when archbishop Nils Allesson visited in Ärentuna parish. The original barrel vault of wood was replaced by brick-made cross-vaults before the church's reopening in 1435. The well-preserved mural paintings, made by unknown “Ärentuna master” date also from 1440-1450s. The bell-tower was reconstructed in 1772.
References:The Walls of Constantinople are a series of defensive stone walls that have surrounded and protected the city of Constantinople (today Istanbul) since its founding as the new capital of the Roman Empire by Constantine the Great. With numerous additions and modifications during their history, they were the last great fortification system of antiquity, and one of the most complex and elaborate systems ever built. They were also the largest and strongest fortification in both the ancient and medieval world.
Initially built by Constantine the Great, the walls surrounded the new city on all sides, protecting it against attack from both sea and land. As the city grew, the famous double line of the Theodosian Walls was built in the 5th century. Although the other sections of the walls were less elaborate, they were, when well-manned, almost impregnable for any medieval besieger.