The curved roof of a ratna temple “is surmounted by one or more towers or pinnacles called ratna (jewel). The simplest form has a single central tower (eka-ratna), to which may be added four more at the corners (pancha-ratna)”. The number of towers or pinnacles can be increased up to a maximum of twentyfive. The ratna style came up in the 15th-16th century. Muslim domed temples are very rare, except possibly in Cooch Behar. “Ratna style temples are the composite type of architecture… The lower part of the temple has all the features of the curved cornices and a short pointed spire crowns the roof and this will be adorned with the introduction of ratnas or kiosks.” Dalan temple The flat-roofed (dalan) temples “with their heavy cornices on S-curved brackets they too have a long Indo-Islamic place and temple tradition” and then was influenced by European ideas in the 19th century. It was easier to build. In the long run, this style lost its special identity as religious architecture and got mixed up with domestic architecture. In some temples a dome has been added, Rekha deul The traditional rekha deul is predominant in the western districts of Bengal. Some are smooth curvilinear and others are ridged curvilinear. In the smooth type, the sikhara is free of horizontal bars and in ridged type, it is closely ridged with bars. The ratha projections are generally deep and spaced, and sometimes decorated. The crowning amalaka is generally large and flat. There are large and small types of deuls. Many of the very small types dispense with the complicated styling. It went on developing from the late 7th century or early 8th century to around the 12th century, increasing its complexity and height but retaining its basic features. Old unspecified temples Grouped temple Temples of identical style and size are sometimes grouped together. Two identical Shiva temples are called a Jora Shiva temple. Groups of four, six and twelve Shiva temples are quite popular. The most elaborate groups existing have 108 Shiva temples. References Sacral architecture Culture of West Bengal Buildings and structures in Bangladesh Hindu temple architecture Indian architectural styles