Michelangelo Buonarroti, Study for the Porta Pia, 1561. Chalk and ink on paper, 44.2 x 28.1 cm. Casa Buonarroti, Florence.
Maerten van Heemskerck, Rome, Old Saint Peter’s Basilica and the Vatican Palace, c. 1535. Brown pen on paper, 27.6 x 62.3 cm. Albertina, Vienna.

Anonymous project for a triumphal arch (France, 19th century)

tower-house . comlongon castle . 15th century . scotland

Teodoro Ardemans - Monte Parnaso (c. 1700).

Giuseppe Galli Bibiena (workshop of) - Sketch for a Catafalque for Louis, Grand Dauphin (c. 1711). Detail.

Château de Coucy - Aisne; Francia - 1220

Restormel Castle, Plan, Lostwithiel, Cornwall, England
Opicinus de Canistris (1296-ca. 1354) Cathedral of Pavia, Avignon, France; 1335-50 Biblioteca Apostolica Vaticana, Vatican City, Pal. Lat. 1993. Via DataDeluge

Andrea Palladio
Plan, elevation and details of the Round Temple (‘Temple of Vesta’) in the Forum Boarium, Rome
mature handwriting
Plan and elevation: ruler and stylus, compasses, pen and brown ink, brush and pale grey wash; details: pen and brown ink, drawn freehand; underdrawing and some calculations in black chalk or graphite; the note at the bottom of the page was added later by Palladio in a darker ink;  London, RIBA Library, Drawings and Archives Collection, SC213/VIII lbr (right)
Palladio Beltramini G, Burns H, 2008,