Conversation so far:
What was Basel in relation to Hans Holbein the Younger?
Basel was where Hans Holbein the Younger worked as a young artist and where he bought a house in St Johanns-Vorstadt.
What did Hans Holbein the Younger use the Basel house for?
Hans Holbein presumably returned home to preserve his citizenship, since he had been granted only a two-year leave of absence to England.
What was significant about Hans Holbein the Younger's house in Basel?
What other things happened during this period in Basel for Hans Holbein the Younger?
Basel's reformist iconoclasts probably destroyed some of Hans Holbein's religious artwork, but details are unknown.
What was significant about that Hans Holbein the Younger's The Artist's Family painting?
Art historian John Rowlands sees The Artist's Family as one of the most moving portraits in art, from an artist...who always characterized his sitters with a guarded restraint.
Did Hans Holbein the Younger have any other famous works?
Portrait of Henry VIII by Hans Holbein the Younger is one of the most iconic images of Henry and is one of the most famous portraits of any British monarch.
Were there any other famous Hans Holbein the Younger paintings?
Hans Holbein the Younger painted the Portrait of Erasmus of Rotterdam and his portraits increased the painter's reputation across Europe, as they and their copies were widely distributed.

Question: What was significant about that commission?
Self-contained rewrite: What was significant about that Hans Holbein the Younger commission by Basel's reformist council?