Parse this person name:

Helena van den Nuwenhuijzen (1214-1280, flourished 1236-1248)
user
first_name: Helena
last_name: van den Nuwenhuijzen
middle_names: []
temporal:
- start: 1214
  end: 1280
  type: life_span
- start: 1236
  end: 1248
  type: flourished
titles: []
extra_info: []
assistant