The recipes were often brief and did not give precise quantities. Cooking times and temperatures were seldom specified since accurate portable clocks were not available and since all cooking was done with fire. At best, cooking times could be specified as the time it took to say a certain number of prayers or how long it took to walk around a certain field. Professional cooks were taught their trade through apprenticeship and practical training, working their way up in the highly defined kitchen hierarchy. A medieval cook employed in a large household would most likely have been able to plan and produce a meal without the help of recipes or written instruction. Due to the generally good condition of surviving manuscripts it has been proposed by food historian Terence Scully that they were records of household practices intended for the wealthy and literate master of a household, such as "Le Ménagier de Paris" from the late 14th century. Over 70 collections of medieval recipes survive today, written in several major European languages.