This interesting surname is Irish. It is a developed form of the ancient Gaelic surname O' Caoindealbhain. The translation is the male descendant of Caoindealbhan, a personal name meaning the son of the comely one (!) and composed of the elements caoin-dealbh and the diminutive suffix -an, meaning little or more likely 'son of'. It can also be a form of the surname O'Conaillain, meaning descendant of Conaillan, a personal name representing a diminutive of Conall, composed of the elements con (from cu meaning hound) plus gal meaning valour. Recordings of the surname are tracebale to the mid 16th century (see below), whilst variations in the idiom of the spelling include Quinlan, Quinlen, Quinelen, Quinlan, and others. One John, son of William and Ann Quinelan, was christened on August 14th 1677, at the church of St. Michan, Dublin, and Betty, daughter of Andrew and Cate Doherty Quinlan, was christened at Rathdowney on April 9th 1765, whilst in London Catherine Quinlan married David Arthur at St. Martin in the Fields, Westminster, on October 10th 1767. The first recorded spelling of the family name is shown to be that of Teag O'Caoinleian. This was dated 1651, in the province of Munster, Ireland, during the reign of Oliver Cromwell, "The Great Protector", 1649 - 1658. Surnames became necessary when governments introduced personal taxation. In England this was known as Poll Tax. Throughout the centuries, surnames in every country have continued to "develop" often leading to astonishing variants of the original spelling.