The stone arch bridge was built over the Tagus River in Alcántara between 104 and 106 AD by an order of the Roman emperor Trajan in 98.
The Alcántara Bridge has suffered more damage from war than from the elements over the years. The Moors destroyed one of the smallest arches in 1214 although this was rebuilt centuries later, in 1543, with stone taken from the original quarries. The second arch on the northwest side was then later destroyed in 1760 by the Spanish to stop the Portuguese advancing and was repaired in 1762 by Charles III, only to be blown up again in 1809 by Wellington's forces attempting to stop the French. Temporary repairs were made in 1819, but much of the bridge was destroyed yet again in 1836 by the Carlists. The bridge was rebuilt in 1860 using mortared masonry. And following completion of the José María de Oriol Dam, which allowed for the draining of the Tagus riverbed, the main pillars were completely repaired in 1969.
The bridge's construction occurred in the ancient Roman province of Lusitania. In Ancient Rome, the costs of building and repairing bridges, known as opus pontis ('bridge work'), were the responsibility of multiple local municipalities. Their shared costs prove Roman bridges belonged to the region overall, and not to any one town (or two, if on a border). The Alcántara Bridge was built at the expense of 12 local municipalities in Lusitania. The names were added on an inscription on the archway over the central pier.
References:Doune Castle was originally built in the thirteenth century, then probably damaged in the Scottish Wars of Independence, before being rebuilt in its present form in the late 14th century by Robert Stewart, Duke of Albany (c. 1340–1420), the son of King Robert II of Scots, and Regent of Scotland from 1388 until his death. Duke Robert"s stronghold has survived relatively unchanged and complete, and the whole castle was traditionally thought of as the result of a single period of construction at this time. The castle passed to the crown in 1425, when Albany"s son was executed, and was used as a royal hunting lodge and dower house.
In the later 16th century, Doune became the property of the Earls of Moray. The castle saw military action during the Wars of the Three Kingdoms and Glencairn"s rising in the mid-17th century, and during the Jacobite risings of the late 17th century and 18th century.