The name Deidra has its origins in the Irish and Gaelic languages, derived from the Old Irish word 'deidghfir,' meaning 'wanderer' or 'stranger.' It first emerged in the early medieval period, around the 5th to 7th centuries CE, when Ireland and parts of Scotland were populated by Celtic tribes and clans.

Deidra was a feminine form of the masculine name Deidghfir, which was commonly used among the ancient Irish and Scots. The earliest known reference to the name can be found in the Annals of Ulster, an ancient chronicle written by medieval Irish monks, which recorded events from the 5th to the 16th centuries.

One of the earliest recorded individuals with the name Deidra was Deidra of Kildare, an Irish noblewoman who lived in the 8th century CE. She was known for her charitable works and her patronage of the famous Kildare Abbey, one of the most significant monasteries in medieval Ireland.

In the 11th century, a woman named Deidra of Connacht was a prominent figure in Irish history. She was the daughter of the King of Connacht, a powerful Irish province, and played a vital role in negotiating peace treaties between warring clans.

During the 12th century, Deidra mac Domhnaill was a renowned Irish poet and bard. She was celebrated for her eloquent verses and her skill in composing intricate poems and songs in the Gaelic language.

In the 15th century, Deidra O'Donnell was a notable figure in the Irish Renaissance. She was a skilled calligrapher and illuminator, known for her beautiful and intricate manuscript illustrations, which adorned many important texts and religious works of the time.

Another historical figure with the name Deidra was Deidra Stewart, a Scottish noblewoman who lived in the 16th century. She was a influential member of the court of King James V of Scotland and played a significant role in the political affairs of the Scottish monarchy during her lifetime.

While the name Deidra was once quite common in Ireland and Scotland, it became less widely used over time. However, it has seen a resurgence in popularity in recent decades, particularly in English-speaking countries, where it is now considered a unique and distinctive name with a rich historical and cultural heritage.