Bertha was a Roman fortress north of the site of modern Perth, in Scotland at the confluence of the rivers Almond and Tay. It is half a mile east of the modern farm of "Berthapark" and is a scheduled ancient monument.
One source contradicts the view that Perth was a corruption of the fort's name. According to this source, the name "Bertha" was originally used by medieval Scots historians, such as John of Fordun and Walter Bower, who did not know the original name for the site and who adapted a version of "Perth" - "Berth". The Romans probably called the site "Tamia", after a native name for the River Tay. In early medieval times the abandoned site was still used for ceremonial purposes by Pictish and Gaelic kings, when it was called "Rathinveramon".
The fort was a supply base built around AD83 to support the occasional Roman expeditions into north-east Scotland. At that time, it was at the highest navigable point on the Tay. It's thought possible that the site was re-used on three occasions up to the 3rd century
The 9-acre (36,000 m2) site was identified in the 18th century. It has been damaged by river erosion and by ploughing, but excavations in 1973 revealed a ditch 11 feet (3.4 m) wide and 5.5 feet (1.7 m) deep. Immediately within the ditch was a wide berm over 30 feet (9.1 m) wide and this was backed by a turf rampart averaging about 21 feet (6.4 m) wide.
- Historic Environment Scotland. "Bertha,Roman fort (SM2403)". Retrieved 15 February 2019.
- "Perth and Bertha". Senchus - Notes on early medieval Scotland. Retrieved 14 September 2009.
- "Perth". Undiscovered Scotland. 2000–2009. Retrieved 14 September 2009.
- "Bertha, Perth, Tayside". Roman Fort and Camps. 27 January 2016. Archived from the original on 1 March 2019. Retrieved 16 March 2016.