私はある画家のアトリエを久しぶりで訪ねたが、その画家は、新しいモデルを手に入れたばかりのところで、大いに上機嫌だつた。

English Translation

I visited the atelier of a painter that I had not visited in a long time. This painter had just acquired a new model and he was in a very good mood.

What’s going on with だつた? I’m not sure how to parse that.

Maybe it’s a typo and it should be だった?