These fortresses were designed to house a cohort of about 500 Roman soldiers.
Near the fort, settlements would grow housing artisans, traders and soldiers' wives and children.
By the mid-7th century, English and Irish missionaries set out to convert the Frisians.
The pope appointed their leader, Willibrordus, bishop of the Frisians.
The tenure of Willibrordus is generally considered to be the beginning of the Bishopric of Utrecht.
In 723, the Frankish leader Charles Martel bestowed the fortress in Utrecht and the surrounding lands as the base of the bishops.
The prince-bishopric was involved in almost continuous conflicts with the Counts of Holland and the Dukes of Guelders.) is a municipality in the Netherlands, capital and most populous city of the province of Utrecht.It is located in the eastern corner of the Randstad conurbation and is the fourth largest city in the Netherlands with a population of 345,080 in 2017.Utrecht's ancient city centre features many buildings and structures several dating as far back as the High Middle Ages.It has been the religious centre of the Netherlands since the 8th century.