Recorded in many unusual forms including Alster, Elster, Allester, Ulster, and Aylster, this very unusual surname is a good example of how words do become transposed over the centuries. It is almost certainly Scottish, and originates from the Gaelic personal name Alastair or Alistair, itself a developed form of the original Greek Alexander. Alexander meaning 'The defender of man' was introduced into Scotland by Queen Margaret of Scotland who died in 1093. She named her third son Alexander, and the name achieved great popularity in the country, with three future kings being so named. The surname of Alexander is very popular on the west coast of Scotland, and there are several families of MacAlexander as well as those called Alexander and Alexanderson. Alastair from Alexander is first found as MacAlaxandair in 1467, and as MacAlistair and other spellings from the early 16th century. In this case the surname is quite well recorded in its different forms in the surviving church registers of the city of London, where the 'Mac' prefix has been dropped. These include the exotically named Fridaysmith Alistair who married Elizabeth Blunt at St Martins in the Field, Westminster, on February 13th 1563, Mary Ulster who married William Dorsett at St Dionis Backchurch, on February 4th 1611, and Henry Elster who married Elizabeth Driver at St Dunstans in the East, Stepney, on January 9th 1861.