Palazzo Caetani

It was built for Alessandro Mattei between 1545 and 1564, and acquired by the Caetani in 1776, from whom the present name comes; it is also called Mattei Caetani and Mattei alle Botteghe Oscure. The architect is not settled: Ammannati has often been given and has recently been doubted, and Baglione mentions a contribution by Vignola without saying whether he designed it. it.wikipedia's article on the street records the Fondazione Camillo Caetani in the building since 1963.