Your plant is a true arum, unlike a peace lily. Here's a very good article on them, with a photo that closely resembles your plant.
This one's Arum maculatum, a common wild plant in Europe, Turkey and other places. It has many common names - in the UK, most commonly called Jack in the Pulpit. This and Arum italica grow separately, but also hybridize. Female flowers produce a short stem of bright red berries in autumn - these are toxic, but not particularly dangerous to humans because they sting/cut the mouth if you try to eat them, thus preventing major consumption. https://en.m.wikipedia.org/wiki/Arum_maculatum
I think it is an Araceae. Peace lily is in such family (Spathiphyllum cochlearispathum)
Maybe an Arum italicum (white veins, normal Arum usually have not much visible white veins). Yellow spate indicate A. italicum (much less frequent on Arum maculatum (usually brown spate)). Arum maculatum is frequent in Europe (wild plant). Arum italicum is probably a cultivated plant, and so often seen near gardens.
But it can be also a Calla. Garden varieties are very diverse.