diff --git a/spacy/tokens/span.pxd b/spacy/tokens/span.pxd
index e072e40d1..eeb663f67 100644
--- a/spacy/tokens/span.pxd
+++ b/spacy/tokens/span.pxd
@@ -3,11 +3,10 @@ from .doc cimport Doc
 
 cdef class Span:
     cdef readonly Doc doc
-    cdef public int i
-    cdef public int start
-    cdef public int end
-    cdef public int start_char
-    cdef public int end_char
+    cdef readonly int start
+    cdef readonly int end
+    cdef readonly int start_char
+    cdef readonly int end_char
     cdef readonly int label
 
     cdef public _vector