This was the family line that I first researched.
I obtained a birth certificate for my grandmother, Alice Irvine, born, Northcote, New Zealand; her father, Francis Oates Irvine, born Leeds, England; and his father, a Doctor, Francis Weymss Irvine, born Sydney, New South Wales in 1822 and his mother Sarah Anne Oates, born Leeds, England in 1824.
Checking at the State Library showed that in Burke's "Landed Gentry", there was an Irvine family 'of Drum', near Aberdeen. This family originated with Sir William de Irwin who was Secretary and Armour-bearer to Robert the Bruce. For his services he was granted the Castle and Forests of Drum in 1323.
Also, another pedigree, that of the Oates family stated: Sarah Anne Oates m June 1848, Francis Weymss Irvine MD, grandson of Alexander Irvine, 18th Laird of Drum, Aberdeen, and died May 1893 leaving issue. He died 5 May 1883.
And so I had found the link to this great family of Scotland. It then was just a matter of following the pedigrees to find the links that the Irvine family had to many other Scottish families, including the Royal Stewarts which in turn led to the pedigrees of the English and European Royalty
My research of this family can be downloaded at Irvine Family History