diff --git a/src/sage/rings/number_field/number_field_ideal.py b/src/sage/rings/number_field/number_field_ideal.py
index 928d48b8107..afea852bd56 100644
--- a/src/sage/rings/number_field/number_field_ideal.py
+++ b/src/sage/rings/number_field/number_field_ideal.py
@@ -56,8 +56,6 @@
 from sage.structure.proof.proof import get_flag
 from sage.structure.richcmp import richcmp
 
-from sage.libs.pari.all import pari_gen, PariError, pari
-
 QQ = rational_field.RationalField()
 ZZ = integer_ring.IntegerRing()
 
@@ -117,6 +115,7 @@ def __init__(self, field, gens, coerce=True):
 
         if len(gens) == 1 and isinstance(gens[0], (list, tuple)):
             gens = gens[0]
+        from sage.libs.pari.all import pari_gen
         if len(gens) == 1 and isinstance(gens[0], pari_gen):
             # Init from PARI
             gens = gens[0]
@@ -1017,28 +1016,13 @@ def is_prime(self):
         K = self.number_field().pari_nf()
         I = self.pari_hnf()
 
-        # The function idealismaximal() is broken prior to PARI 2.13.4.
-        if pari.version() >= (2, 13, 4):
-            self._pari_prime = K.idealismaximal(I) or None
-            # PARI uses probabilistic primality testing inside idealismaximal().
-            if self._pari_prime \
-                    and get_flag(None, 'arithmetic') \
-                    and not self._pari_prime[0].isprime():
-                self._pari_prime = None
-        else:
-            # For other PARI versions, we factor I, but only if the norm is a prime power.
-            #TODO This can be removed once support for PARI < 2.13.4 has been phased out.
+        self._pari_prime = K.idealismaximal(I) or None
+
+        # PARI uses probabilistic primality testing inside idealismaximal().
+        if self._pari_prime \
+                and get_flag(None, 'arithmetic') \
+                and not self._pari_prime[0].isprime():
             self._pari_prime = None
-            n = self.norm()
-            try:
-                n = ZZ(n)
-            except TypeError:
-                return False
-            if not n.is_prime_power():
-                return False
-            F = self.factor()  # factorization with caching
-            if len(F) == 1 and F[0][1] == 1:
-                self._pari_prime = F[0][0]._pari_prime
 
         return self._pari_prime is not None
 
@@ -2577,6 +2561,7 @@ def _pari_bid_(self, flag=1):
             sage: bid.getattr('clgp')
             [2, [2]]
         """
+        from sage.libs.pari.all import PariError
         try:
             bid = self._bid
             if flag == 2: