Oristano and San Giovanni Sinis

We got out of the ferry port at Cagliari at 9am so being Sunday decided to head straight up to Oristano, find our accomodation (check in 12.30) so check out the centre first! After exploring  Oristano centre we checked in and met the delightful Salvatori our host who was most welcoming giving us as the first arrivals our choice of rooms! once settled in Salvatori suggested a place to visit in the afternoon - San Giovanni Sinis which reputably has the oldest church in Sardinia?