Throughout the series, it has been noted that Alf's family founded Summer Bay. Alf was born in Summer Bay as was his father and paternal grandfather. His Summer Bay founder great grandfather's origins disappear into the midsts of Scotland, 10'000 miles away from Australia.
Parents of:- Duncan Stewart Snr born c1870
Duncan Stewart married Unknown Woman c1905
Gordon Stewart married Sarah Jane Townsend in 1939.
Gordon Stewart had relationship with Mavis Hickle in 1939
Colleen Hickle (later Smart) born 1940.
Coleen Hickle had relationship with Unknown Man in 1954
Maureen Evans born 1955
Coleen Hickle married Les Smart in 1965
Lance Smart born 1968
Alf Stewart married Martha Baldivis in 1969
Roo Stewart born 1970
Alf Stewart married Ailsa O'Rourke in 1988
Duncan Stewart born 1989 (later SORASed) to 1986
Morag Bellingham (nee Stewart) had relationship with Donald Fisher in 1970
Bobby Marshall born 1970
Mr Stewart* married Unknowm Woman c1945
Jennifer Stewart later Atkinson born c1955.
The Stewart family can be traced back several generations to the Scottish "immigrant" Angus Stewart who first stepped on Australian soil in May 1852. The ship he sailed on was was full of immigrants instead of convicts. Summer Bay residents seem to be mainly of Scottish or English ancestry as a result. The Summer Bay's version of the Mayflower. Angus was around 20-25 years old and his origins disappear in the midsts of Scotland.
Alf Stewart, the now 70 year old patriarch of Summer Bay is the great grandson of Angus.
Flamin' Alf has always spoke of his Scottish roots and has spoken of this a lot. In 2010 he planned a trip to Scotland to study the clan Stewart. In 1994, he and Ailsa learned Scottish dancing.
Lovers Bobby and Alan never knew they were half siblings, and first cousins until after Alan died due to his brain aneurysm 
Alan and Bobby are the half cousins of Lance Smart, they share 1 grandparent.
Some sources say Angus Stewart was a cabin boy rather than the captain, nevertheless he founded Summer Bay.