The Onchan Christians are descendants of the Christalsons as opposed to the MacChristins.

In 1511 the Christalsons held part of Clypse Moar and part of Ballacottier in the Treen of Slekby and the whole of Glencrutchery in the Treen of Tremott. All these in Onchan.

In the 1540 rent roll, there is a Fynlo Christalson in Lonan, and in Onchan there are
Christall Christalson (male!); Donald, Gibbon, John, Mark, and William. The latter also held property in Douglas.

By 1567 their holdings were:

John - Glencrutchery
John - Begoad
William - Ballig (part)
Donald - Ballacottier & Ballaskelley (parts)

At this date the quarterland of Slegaby was held by John Creer, but later the Creers held Clypse and the Christians held Slegaby.

I have not personally traced the line of descent of the C's of Slegaby.