Radama's successor Ranavalona I invited a shipwrecked craftsman named Jean Laborde to construct the tomb of Prime Minister Rainiharo, and Manjakamiadana (built 1839–1841), the largest palace at the Rova. Laborde also produced a wide range of industrial products at factories in the highland village Mantasoa and a foundry in the Antananarivo neighborhood Isoraka. Ranavalona oversaw improvements to the city's infrastructure, including the construction of the city's two largest staircases at Antaninarenina and Ambondrona, which connect ''la ville moyenne'' ("the middle town") to the central marketplace at Analakely. In 1867, following a series of fires in the capital, Queen Ranavalona II issued a royal decree that permitted the use of stone and brick construction in buildings other than tombs. LMS missionaries' first brick house was built in 1869; it bore a blend of English, Creole and Malagasy design and served as a model for a new style of house that rapidly spread throughout the capital and across the highlands. Termed the ''trano gasy'' ("Malagasy house"), it is typically a two-story, brick building with four columns on the front that support a wooden veranda. In the latter third of the 19th century, these houses quickly replaced most of the traditional wooden houses of the city's aristocratic class. The growing number of Christians in Imerina prompted the construction of stone churches throughout the highlands, as well as four memorial churches on key sites of martyrdom among early Malagasy Christians under the reign of Ranavalona I.