Two Galactic isolated strong X-ray pulsars seem to be in the densest environments compared to other types of Galactic pulsar. X-ray pulsar J1846-0258 can be in an early phase of anomalous X-ray pulsars and soft gamma repeaters if its average braking index is similar to 1.8-2.0. X-ray pulsar J1811-1925 must have a very large average braking index (similar to 11) if this pulsar was formed by SN 386AD. This X-ray pulsar can be in an early phase of the evolution of the radio pulsars located in the region P similar to 50-150 ms and P similar to 10(-14)-10(-16) ss(-1) of the P-P diagram. X-ray/radio pulsar J0540-69 seems to be evolving in the direction to the dim isolated thermal neutron star region on the P-P diagram. Possible progenitors of different types of neutron star are also discussed.