The Museum Condes de Castro Guimarães, the former “Torre de S. Sebastião”, was built in 1900 by Jorge O’Neill. A classic example of “summer architecture”, the building features ecletic elements, inviting visitors to enter a kingdom of fantasy and wonder celebrated in this XIXth century revival of the era of romance.

In 1910, the Count Manuel de Castro Guimarães aquires the house and after is dead (1927) donated his state, including his garden, to the people of Cascais. His desire was to built an art museum and a public library. The museum opened on July 12, 1931.

The Museum Condes de Castro Guimarães collection includes significant national and international paintings, furniture, porcelain and jewellery. Another important part of museum collection is the Crónica de El-Rei D. afonso Henriques (Chronicle of King Afonso Henriques) (1505) by Duarte Galvão, whose Prologue page includes artwork by the miniaturistAntónio d’Ollanda.