The three Adas were all ancestors of the British royal family and the name Ada was a family name, which probably originated as Adeline or Adelaide.
The first Ada was Ada de Warenne who was born circa 1120 as the daughter of William de Warenne, 2nd Earl of Surrey and Elisabeth of Vermandois. Ada married Prince Henry of Scotland, Earl of Northumbria and Earl of Huntingdon in 1139 and they were the parents of two Kings of Scots.
She missed out on being Queen of Scots when her husband died in 1152 and her father-in-law in 1153. Her son Malcolm was installed as King of Scots, while his brother William became Earl of Northumbria. Ada retired to her lands in Haddington. Ada devoted her time to charity and improving the church at Haddington. She even founded a convent. Her youngest daughter was Ada of Huntingdon, named after herself. She died in 1178 and is buried in Kelso Abbey.
Ada of Huntingdon was born circa 1146, and not much is known of her youth. She married Floris III, Count of Holland in 1162 in Egmond and she received the County of Ross as a wedding gift. Ada and Floris had between 8 and 11 children of whom some died young. Floris died in 1190 during the third Crusade of pestilence, and his remains were buried in Antioch. Two of their sons became Count of Holland. Ada herself died in 1206 and was probably buried in the Abbey of Middelburg. The tomb was probably lost during a great fire in 1492. Her eldest daughter was another Ada.
Ada of Holland was born circa 1163. Again, not much is known of her youth. She married Otto I of Brandenburg in 1176 as his second wife. His first wife was Judith of Poland, and he had two sons by her. Ada and Otto had at least one son, Albert, who would later succeed his half-brothers. Through Albert, the three Ada’s are the ancestors of all British monarchs since 1714. Otto died in 1184, and Ada died in 1205, being outlived by her mother. It is not even known where she was buried.
Two bonus Ada’s were the last Ada’s niece, also Ada of Holland, heiress of Holland as the only surviving child of Dirk VII of Holland, the last Ada’s brother. She is also the first Ada of whom we have a portrait! She’ll have her own article later on.
The other bonus Ada is another Ada of Holland, daughter of William I, Count of Holland, born between 1197 and 1218. She lived a very religious life as firstly a nun and later as the Abbess of Rijnsburg. She died 1258 and was buried at Rijnsburg at the high altar. The tombstone can now be found in the wall of the choir as the abbey was almost completely destroyed.