Platain House and the one backing onto it share the same roof. Platain House, built in ashlar and brickwork, would appear to date from the 16th Century. It has interesting carved stone eaves and a gallery opening out onto the adjacent garden. The building alongside it, dating from the 18th Century, has a sober ashlar facade and interesting eaves and balconies; this is a typical example of terraced housing in a deep, narrow area.
Platain House stood, along with another two houses, apart from the others separated by a beach towards the north which could only be crossed at low tide.
In 1546, the owners of the three buildings were ordered by the Mayor and Fuenterrabía Regiment to build a road which could be used at low tide to link their houses with Bizkaia House.
One of these houses, probably that belonging to Juan Villaviciosa, standing at the end of the square, later acquired the name of Colegialenea due to the fact that it was inhabited by a doctor or collegiate member. It has a shield on its facade, probably rescued from among the ruins of Platain House, the legendary hero related to the Villaviciosa and Arizabalo families.
Platain was a legendary character evoking memories of the local roots about whom little is known.