Complex sentence: She co-wrote the book "Gudelika Snillis Väckiare" with her colleague Kadrin or Katarina (d.1519), which was published in the early 16th century, making them the perhaps first female book writers of their country.
Split into simpler sentences: She co-wrote the book "Gudelika Snillis Väckiare" with her colleague Kadrin or Katarina (d.1519), which was published in the early 16th century. Thereby making them the perhaps first female book-writers of their country.