From the end of the 18th century writing boxes were being used everywhere on travels, in libraries and at home. These were very personal items and used for both business and personal writing.
There are many styles of writing box. Some contain just the accoutrements of writing for prolific writers, calligraphers or manuscript illustrators. Others become writing slopes and there are those which are shaped as one would expect a writing slope.
Writing slopes are more often used at ceremonies and official events today. However, some institutions now sell writing slopes for their ergonomic benefit.