Parse this person name:

Brian Geertsen, 1537-1583, flourished 1557-1578
user
first_name: Brian
last_name: Geertsen
middle_names: []
temporal:
- start: 1537
  end: 1583
  type: life_span
- start: 1557
  end: 1578
  type: flourished
titles: []
extra_info: []
assistant