sentence1: The prize pieces of this stunning collection include Piero della Francesca's San Nicola da Tolentino, Mantegna's Madonna and Child, a Botticelli Madonna, and Antonio Pollaiuolo's lovely Portrait of a Young Woman.
sentence2: Piero della Francesca's San Nicola da Tolentino, Mantegna's Madonna and Child, a Botticelli Madonna, and Antonio Pollaiuolo's Portrait of a Young Woman are the most popular and valuable pieces in this collection.