 Purves and Lane stepped down from their roles at around the same time and were replaced by Anneke Wills and Michael Craze who played Polly and Ben Jackson.Patrick Troughton took over from Hartnell in the fourth season as the Second Doctor and starred alongside Wills and Craze and, after they stepped down, Deborah Watling, Frazer Hines and Wendy Padbury who respectively played Victoria Waterfield, Jamie McCrimmon and Zoe Heriot.At the end of "The War Games", Troughton was replaced by Jon Pertwee who began his run as the Third Doctor alongside Caroline John as Liz Shaw in the 1970 serial; "Spearhead from Space".