Simplify the following text for a Grade 9 native English-speaking person.
Original: There are now two algorithms commonly used , Prim 's algorithm and Kruskal 's algorithm .
Simplified: Edsger Wybe Dijkstra rediscovered it in 1959 , and called it Prim 's algorithm . The other algorithm is called Kruskal 's algorithm , and was pulbished by Joseph Kruskal in 1956 .