Parse this person name:

Kyra van der Steen, 1217-1278, flourished 1235-1259
user
first_name: Kyra
last_name: van der Steen
middle_names: []
temporal:
- start: 1217
  end: 1278
  type: life_span
- start: 1235
  end: 1259
  type: flourished
titles: []
extra_info: []
assistant