I am looking for information on ERNST HANSBERG, my great grandfather.

It's a long shot, but I only know that he married MARGOT HOLM, in Tallinn, Estonia, prior to 1910.

They had a son, (my grandfather) HARALD HEINRICH HANSBERG.

ERNST died of pneumonia on 7 January 1912, when HARALD was not quite 13 months old.

HARALD had a sister, INGRID... but I do not know if ERNST is her father as well... perhaps MARGOT was pregnant when ERNST died?