Parse this person name:

Friedhelm Jäntsch (1217-1269, flourished 1238-1251)
user
first_name: Friedhelm
last_name: Jäntsch
middle_names: []
temporal:
- start: 1217
  end: 1269
  type: life_span
- start: 1238
  end: 1251
  type: flourished
titles: []
extra_info: []
assistant