Sarrià-Sant Gervasi is one of the biggest districts of Barcelona. It's the district with the highest per capita income, the largest proportion of university degrees, the lowest unemployment rate and the lowest percentage of foreigners. Situated on the north-west of the city, surrounded by the districts of Les Corts, Gràcia, and Eixample i Horta-Guinardo and by the villages of Sant Just, Sant Feliu, Molins de Rei, and Sant Cugat. It is formed by the old villages of Sarrià, Vallvidrera, Santa Creu d'Olorda, and Sant Gervasi de Cassoles. The first written document found about Sarrià dates from the year 987, and the origins of the village are a Roman colony. The old Monestir de Pedralbes belonged to the village of Sarrià, and it is now the Museo Thyssen-Bornemisza.