The Dicalydones were mentioned by the 4th century writer Ammianus Marcellinus

Ammianus Marcellinus

Ammianus Marcellinus was a fourth-century Roman historian. He wrote the penultimate major historical account surviving from Antiquity...

 as one of the two branches of the Picti, the Picts

Picts

The Picts were a group of Late Iron Age and Early Mediaeval people living in what is now eastern and northern Scotland. There is an association with the distribution of brochs, place names beginning 'Pit-', for instance Pitlochry, and Pictish stones. They are recorded from before the Roman conquest...

, the inhabitants of modern-day Scotland

Scotland

Scotland is a country that is part of the United Kingdom. Occupying the northern third of the island of Great Britain, it shares a border with England to the south and is bounded by the North Sea to the east, the Atlantic Ocean to the north and west, and the North Channel and Irish Sea to the...

 (the other being the Verturiones).

The name bears a striking resemblance to the other historical nomenclature donated to the Picts by classical historians, Caledonii. Some scholars theorize that the two groups (Dicalydones and Caledonii) are one and the same, and that the other major Pictish tribes, related by Ptolemy

Ptolemy

Claudius Ptolemy , was a Roman citizen of Egypt who wrote in Greek. He was a mathematician, astronomer, geographer, astrologer, and poet of a single epigram in the Greek Anthology. He lived in Egypt under Roman rule, and is believed to have been born in the town of Ptolemais Hermiou in the...

 as the Vacomagi

Vacomagi

The Vacomagi were a people of ancient Britain, known only from a single mention of them by the geographer Ptolemy c. 150. From his general description and the approximate locations of their neighbors, their territory was the region of Strathspey, including that part of the northern coast of Scotland...

, Venicones

Venicones

The Venicones were a people of ancient Britain, known only from a single mention of them by the geographer Ptolemy c. 150 AD. He recorded that their town was 'Orrea'. This has been identified as the Roman fort of Horrea Classis, located by Rivet and Smith as Monifieth, six miles east of Dundee....

, and Taezali, eventually went on to form the Maeatae

Maeatae

The Maeatae were a confederation of tribes who lived probably beyond the Antonine Wall in Roman Britain. The historical sources are vague as to the exact region they inhabited....

mentioned by Cassius Dio. Other archaic accounts, which mention the Caledonii and Maeatae as the two major Pictish tribes, would seem to corroborate this hypothesis.