Early modern era

Since swimming was done in a state of undress, it became less popular as society became more conservative in the early Modern period. Leonardo da Vinci made early sketches of lifebelts. In 1538, Nikolaus Wynmann, a Swiss–German professor of languages, wrote the earliest known complete book about swimming, Colymbetes, sive de arte natandi dialogus et festivus et iucundus lectu (The Swimmer, or A Dialogue on the Art of Swimming and Joyful and Pleasant to Read).  His purpose was to reduce the dangers of drowning. The book contained a good methodical approach to learning breaststroke, and mentioned swimming aids such as air filled cow bladders, reed bundles, and cork belts.

In 1587, Everard Digby also wrote a swimming book, claiming that humans could swim better than fish. Digby was a Senior Fellow at St. John's College, Cambridge and was interested in the scientific method. His short treatise, De arte natandi, was written in Latin and contained over 40 woodcut illustrations depicting various methods of swimming, including the breaststroke, backstroke and crawl. Digby regarded the breaststroke as the most useful form of swimming.

 In 1603, Emperor Go-Yozei of Japan declared that schoolchildren should swim.

In 1595, Christopher Middleton wrote "A short introduction for to learne to swimme", that was the first published guide recording drawings and examples of different swimming styles.

In 1696, the French author Melchisédech Thévenot wrote The Art of Swimming, describing a breaststroke very similar to the modern breaststroke. This book was translated into English and became the standard reference of swimming for many years to come. In 1793, GutsMuths from Schnepfenthal, Germany, wrote Gymnastik für die Jugend (Exercise for youth), including a significant portion about swimming. In 1794, Kanonikus Oronzio de Bernardi of Italy wrote a two volume book about swimming, including floating practice as a prerequisite for swimming studies.

In 1798, GutsMuths wrote another book Kleines Lehrbuch der Schwimmkunst zum Selbstunterricht (Small study book of the art of swimming for self-study), recommending the use of a "fishing rod" device to aid in the learning of swimming. His books describe a three-step approach to learning to swim that is still used today. First, get the student used to the water; second, practice the swimming movements out of the water; and third, practice the swimming movements in the water. He believed that swimming is an essential part of every education. The Haloren, a group of salt makers in Halle, Germany, greatly advanced swimming through setting a good example to others by teaching their children to swim at a very early age.