He is married to Isabel Robertson.
They got married
Child(ren):
file://///T300/DATA-T300/!_Sites/Stirnet/www.stirnet.com/genie/data/british/mm4fz/moncreiff01.html
E: Moncreiffe in Kirkwall (d c1625)
m. Isabel Robertson (dau of William Robertson of Struan)
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http://www.electricscotland.com/webclans/m/houseofmoncrieff00seto.pdf
named John, not David